485BPOS

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, DC 20549

FORM N-1A

File No. 002-37707
File No. 811-02071

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933		/X/
	Pre-Effective Amendment No.	/   /
	Post-Effective Amendment No.        84	/X/
		and/or
REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940		/X/
	Amendment No.       84

(Check appropriate box or boxes.)
DELAWARE GROUP INCOME FUNDS
(Exact Name of Registrant as Specified in Charter)
	2005 Market Street, Philadelphia, Pennsylvania	19103-7094
	(Address of Principal Executive Offices)	(Zip Code)

Registrant’s Telephone Number, including Area Code: (800) 523-1918

David F. Connor, Esq., 2005 Market Street, Philadelphia, PA 19103-7094

(Name and Address of Agent for Service)

It is proposed that this filing will become effective (check appropriate box):

/X/	immediately upon filing pursuant to paragraph (b)
/   /	on (date) pursuant to paragraph (b)
/   /	60 days after filing pursuant to paragraph (a)(1)
/   /	on (date) pursuant to paragraph (a)(1)
/   /	75 days after filing pursuant to paragraph (a)(2)
/   /	on (date) pursuant to paragraph (a)(2) of Rule 485.
If appropriate, check the following box:
/   /	this post-effective amendment designates a new effective date for a previously filed post-effective amendment.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant certifies that it meets all of the requirements for effectiveness of this Registration Statement under Rule 485(b) under the Securities Act of 1933 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Philadelphia and Commonwealth of Pennsylvania on this 19th day of December, 2012.

DELAWARE GROUP INCOME FUNDS
By:	/s/ Patrick P. Coyne
	Patrick P. Coyne
	Chairman/President/Chief Executive Officer

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed below by the following persons in the capacities and on the dates indicated:

Signature		Title	Date
/s/ Patrick P. Coyne		Chairman/President/Chief Executive Officer	December 19, 2012
Patrick P. Coyne		(Principal Executive Officer) and Trustee
Thomas L. Bennett	*	Trustee	December 19, 2012
Thomas L. Bennett
John A. Fry	*	Trustee	December 19, 2012
John A. Fry
Anthony D. Knerr	*	Trustee	December 19, 2012
Anthony D. Knerr
Lucinda S. Landreth	*	Trustee	December 19, 2012
Lucinda S. Landreth
Frances A. Sevilla-Sacasa	*	Trustee	December 19, 2012
Frances A. Sevilla-Sacasa
Janet L. Yeomans	*	Trustee	December 19, 2012
Janet L. Yeomans
J. Richard Zecher	*	Trustee	December 19, 2012
J. Richard Zecher
Richard Salus	*	Senior Vice President/Chief Financial Officer	December 19, 2012
Richard Salus		(Principal Financial Officer)

	By:	/s/ Patrick P. Coyne
Patrick P. Coyne
as Attorney-in-Fact for
each of the persons indicated
(Pursuant to Powers of Attorney previously filed)

2

INDEX TO EXHIBITS
(Delaware Group^® Income Funds N-1A)

Exhibit No.	Exhibit
EX-1-101.INS	XBRL Instance Document
EX-1-101.SCH	XBRL Taxonomy Extension Schema Document
EX-1-101.DEF	XBRL Taxonomy Extension Definition Linkbase
EX-1-101.LAB	XBRL Taxonomy Extension Labels Linkbase
EX-1-101.PRE	XBRL Taxonomy Extension Presentation Linkbase

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Average Annual Total Returns (dei_DocumentInformationDocumentAxis)	0 Months Ended
	Nov. 28, 2012
(Delaware Core Bond Fund) | Barclays U.S. Aggregate Index (reflects no deduction for fees, expenses, or taxes)
Average Annual Return:
1 Year	7.84%
5 Years	6.50%
10 years or lifetime	5.78%
(Delaware Core Bond Fund) | Class A
Average Annual Return:
1 Year	3.12%
5 Years	5.66%
10 years or lifetime	5.07%
(Delaware Core Bond Fund) | Class A | return after taxes on distributions
Average Annual Return:
1 Year	1.14%
5 Years	3.94%
10 years or lifetime	3.36%
(Delaware Core Bond Fund) | Class A | return after taxes on distributions and sale of Fund shares
Average Annual Return:
1 Year	2.05%
5 Years	3.81%
10 years or lifetime	3.30%
(Delaware Core Bond Fund) | Class C
Average Annual Return:
Label	(lifetime: 9/30/09-12/31/11)
1 Year	6.17%
5 Years
Lifetime	5.91%
(Delaware Core Bond Fund) | Institutional Class
Average Annual Return:
Label	(lifetime: 9/30/09-12/31/11)
1 Year	8.31%
5 Years
Lifetime	7.23%
(Delaware Core Bond Fund) | Class R
Average Annual Return:
Label	(lifetime: 9/30/09-12/31/11)
1 Year	7.06%
5 Years
Lifetime	6.38%
(Delaware Corporate Bond Fund) | Barclays U.S. Corporate Investment Grade Index (reflects no deduction for fees, expenses, or taxes)
Average Annual Return:
1 Year	8.15%
5 Years	6.82%
10 years or lifetime	6.36%
(Delaware Corporate Bond Fund) | Class A
Average Annual Return:
1 Year	2.41%
5 Years	6.79%
10 years or lifetime	7.27%
(Delaware Corporate Bond Fund) | Class A | return after taxes on distributions
Average Annual Return:
1 Year	0.03%
5 Years	4.32%
10 years or lifetime	4.88%
(Delaware Corporate Bond Fund) | Class A | return after taxes on distributions and sale of Fund shares
Average Annual Return:
1 Year	1.75%
5 Years	4.35%
10 years or lifetime	4.82%
(Delaware Corporate Bond Fund) | Class B
Average Annual Return:
1 Year	2.70%
5 Years	6.80%
10 years or lifetime	7.12%
(Delaware Corporate Bond Fund) | Class C
Average Annual Return:
1 Year	5.51%
5 Years	6.98%
10 years or lifetime	6.97%
(Delaware Corporate Bond Fund) | Institutional Class
Average Annual Return:
1 Year	7.57%
5 Years	8.09%
10 years or lifetime	8.04%
(Delaware Corporate Bond Fund) | Class R
Average Annual Return:
Label	(lifetime: 6/2/03-12/31/11)
1 Year	7.04%
5 Years	7.52%
Lifetime	6.33%
(Delaware Extended Duration Bond Fund) | Barclays Long U.S. Corporate Index (reflects no deduction for fees, expenses, or taxes)
Average Annual Return:
1 Year	15.91%
5 Years	8.51%
10 years or lifetime	7.98%
(Delaware Extended Duration Bond Fund) | Class A
Average Annual Return:
1 Year	11.22%
5 Years	9.72%
10 years or lifetime	9.44%
(Delaware Extended Duration Bond Fund) | Class A | return after taxes on distributions
Average Annual Return:
1 Year	8.14%
5 Years	7.04%
10 years or lifetime	6.81%
(Delaware Extended Duration Bond Fund) | Class A | return after taxes on distributions and sale of Fund shares
Average Annual Return:
1 Year	7.60%
5 Years	6.76%
10 years or lifetime	6.59%
(Delaware Extended Duration Bond Fund) | Class B
Average Annual Return:
1 Year	11.66%
5 Years	9.68%
10 years or lifetime	9.27%
(Delaware Extended Duration Bond Fund) | Class C
Average Annual Return:
1 Year	14.64%
5 Years	9.92%
10 years or lifetime	9.13%
(Delaware Extended Duration Bond Fund) | Institutional Class
Average Annual Return:
1 Year	16.81%
5 Years	10.99%
10 years or lifetime	10.21%
(Delaware Extended Duration Bond Fund) | Class R
Average Annual Return:
Label	(lifetime: 10/3/05-12/31/11)
1 Year	16.20%
5 Years	10.45%
Lifetime	9.15%
(Delaware High-Yield Opportunities Fund) | BofA Merrill Lynch U.S. High Yield Constrained Index (reflects no deduction for fees, expenses, or taxes)
Average Annual Return:
1 Year	4.37%
5 Years	7.55%
10 years or lifetime	8.74%
(Delaware High-Yield Opportunities Fund) | Class A
Average Annual Return:
1 Year	(2.79%)
5 Years	5.00%
10 years or lifetime	8.31%
(Delaware High-Yield Opportunities Fund) | Class A | return after taxes on distributions
Average Annual Return:
1 Year	(5.42%)
5 Years	2.00%
10 years or lifetime	5.17%
(Delaware High-Yield Opportunities Fund) | Class A | return after taxes on distributions and sale of Fund shares
Average Annual Return:
1 Year	(1.81%)
5 Years	2.43%
10 years or lifetime	5.21%
(Delaware High-Yield Opportunities Fund) | Class B
Average Annual Return:
1 Year	(2.34%)
5 Years	5.03%
10 years or lifetime	8.18%
(Delaware High-Yield Opportunities Fund) | Class C
Average Annual Return:
1 Year	0.25%
5 Years	5.19%
10 years or lifetime	8.03%
(Delaware High-Yield Opportunities Fund) | Institutional Class
Average Annual Return:
1 Year	2.20%
5 Years	6.29%
10 years or lifetime	9.14%
(Delaware High-Yield Opportunities Fund) | Class R
Average Annual Return:
Label	(lifetime: 6/2/03-12/31/11)
1 Year	1.71%
5 Years	5.76%
Lifetime	7.98%
(Delaware Diversified Floating Rate Fund) | BofA Merrill Lynch U.S. Dollar 3-Month LIBOR Constant Maturity Index (reflects no deduction for fees, expenses, or taxes)
Average Annual Return:
1 Year	0.27%
Lifetime	0.31%	[1]
(Delaware Diversified Floating Rate Fund) | Class A
Average Annual Return:
1 Year	(2.56%)
Lifetime	0.07%	[1]
(Delaware Diversified Floating Rate Fund) | Class A | return after taxes on distributions
Average Annual Return:
1 Year	(3.26%)
Lifetime	(0.68%)	[1]
(Delaware Diversified Floating Rate Fund) | Class A | return after taxes on distributions and sale of Fund shares
Average Annual Return:
1 Year	(1.67%)
Lifetime	(0.37%)	[1]
(Delaware Diversified Floating Rate Fund) | Class C
Average Annual Return:
1 Year	(1.54%)
Lifetime	0.85%	[1]
(Delaware Diversified Floating Rate Fund) | Institutional Class
Average Annual Return:
1 Year	0.44%
Lifetime	1.86%	[1]
(Delaware Diversified Floating Rate Fund) | Class R
Average Annual Return:
1 Year	(0.79%)
Lifetime	1.33%	[1]

[1] Lifetime (2/26/10-12/31/11)

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(Delaware Core Bond Fund)

What is the Fund's investment objective?

Delaware Core Bond Fund seeks maximum long-term total return, consistent with reasonable risk.

What are the Fund's fees and expenses?

The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Shareholder fees (fees paid directly from your investment)

Shareholder Fees (Delaware Core Bond Fund)	Class A	Class C		Class R	Institutional Class
Maximum sales charge (load) imposed on purchases as a percentage of offering price	4.50%	none		none	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none	1.00%	[1]	none	none

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses (Delaware Core Bond Fund)		Class A	Class C	Class R	Institutional Class
Management fees		0.50%	0.50%	0.50%	0.50%
Distribution and service (12b-1) fees		0.30%	1.00%	0.60%	none
Other expenses		0.54%	0.54%	0.54%	0.54%
Total annual fund operating expenses		1.34%	2.04%	1.64%	1.04%
Fee waivers and expense reimbursements	[1]	(0.44%)	(0.39%)	(0.49%)	(0.39%)
Total annual fund operating expenses after fee waivers and expense reimbursements		0.90%	1.65%	1.15%	0.65%

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and reflects the applicable waivers and reimbursements for the 1-year contractual period and the total operating expenses without waivers for years 2 through 10. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example (Delaware Core Bond Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	538	814	1,111	1,953
Class C	268	602	1,062	2,338
Class R	117	469	846	1,903
Institutional Class	66	292	536	1,236

Expense Example, No Redemption (Delaware Core Bond Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class C	168	602	1,062	2,338

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 517% of the average value of its portfolio.

What are the Fund's principal investment strategies?

The Fund will invest primarily in a diversified portfolio of investment grade, fixed income obligations, including securities issued or guaranteed by the U.S. government, its agencies or instrumentalities (U.S. government securities), mortgage-backed securities, asset-backed securities, corporate bonds, and other fixed income securities.

Under normal circumstances, the Fund will invest at least 80% of its net assets in fixed income securities (80% Policy). The Fund's 80% Policy may be changed without shareholder approval. However, shareholders will be given notice at least 60 days prior to any such change.

The Fund will invest principally in debt obligations issued or guaranteed by the U.S. government and by U.S. corporations. The U.S. government securities in which the Fund may invest include a variety of securities that are issued or guaranteed as to the payment of principal and interest by the U.S. government, and by various agencies or instrumentalities that have been established or sponsored by the U.S. government. The corporate debt obligations in which the Fund may invest include, but are not limited to, bonds, notes, debentures, and commercial paper of U.S. companies.

The Fund's assets may also be invested in mortgage-backed securities issued or guaranteed by the U.S. government, its agencies or instrumentalities, or by government-sponsored corporations. Other mortgage-backed securities in which the Fund may invest are issued by certain private, nongovernment entities. Subject to quality limitations, the Fund may also invest in securities that are backed by assets such as receivables on home equity and credit card loans, automobile, mobile home, recreational vehicle and other loans, wholesale dealer floor plans, and leases.

All securities purchased by the Fund will have an investment grade rating at the time of purchase. Investment grade fixed income obligations will be those rated BBB- or higher by S&P, Baa3 or higher by Moody's, or similarly rated by another nationally recognized statistical rating organization (NRSRO), or those that are deemed to be of comparable quality. To the extent that the rating of a debt obligation held by the Fund falls below investment grade, the Fund, as soon as practicable, will dispose of the security, unless such disposal would be detrimental to the Fund in light of market conditions.

The Fund may invest up to 20% of its assets in foreign securities. The Fund intends to invest its foreign assets primarily in fixed income securities of issuers organized or having a majority of their assets or deriving a majority of their operating income in foreign countries. These fixed income securities include foreign government securities, debt obligations of foreign companies, and securities issued by supranational entities. The Fund may invest in securities issued in any currency and may hold foreign currencies. Presently, the Fund intends to invest its foreign assets primarily in U.S. dollar-denominated fixed income securities in a manner consistent with the foreign securities weighting in the Fund's benchmark, the Barclays U.S. Aggregate Index.

In unusual market conditions, in order to meet redemption requests, for temporary defensive purposes, and pending investment, the Fund may hold a substantial portion of its assets in cash or short-term fixed income obligations. Subject to certain limitations, the Fund will also be permitted to use various derivative instruments, including options, futures contracts, options on futures contracts, foreign currency transactions, interest rate swaps, and index swap agreements.

What are the principal risks of investing in the Fund?

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio. Principal risks include:

Investments not guaranteed by the Manager or its affiliates — Investments in the Fund are not and will not be deposits with or liabilities of Macquarie Bank Limited ABN 46 008 583 542 and its holding companies, including their subsidiaries or related companies (Macquarie Group), and are subject to investment risk, including possible delays in repayment and loss of income and capital invested. No Macquarie Group company guarantees or will guarantee the performance of the Fund, the repayment of capital from the Fund, or any particular rate of return.

Market risk — The risk that all or a majority of the securities in a certain market — such as the stock or bond market — will decline in value because of factors such as adverse political or economic conditions, future expectations, investor confidence, or heavy institutional selling.

Interest rate risk — The risk that securities will decrease in value if interest rates rise. This risk is generally associated with bonds.

Credit risk — The risk that an issuer of a debt security, including a governmental issuer, may be unable to make interest payments and repay principal in a timely manner.

Prepayment risk — The risk that the principal on a bond that is held by a portfolio will be prepaid prior to maturity at a time when interest rates are lower than what that bond was paying. A portfolio may then have to reinvest that money at a lower interest rate.

Liquidity risk — The possibility that securities cannot be readily sold within seven days at approximately the price at which a fund has valued them.

Derivatives risk — Derivative contracts, such as options, futures, and swaps, may involve additional expenses (such as the payment of premiums) and are subject to significant loss if a security, or a securities index to which a derivative contract is associated, moves in the opposite direction from what the portfolio manager anticipated. Derivative contracts are also subject to the risk that the counterparty may fail to perform its obligations under the contract due to financial difficulties (such as a bankruptcy or reorganization).

Foreign risk — The risk that foreign securities (particularly in emerging markets) may be adversely affected by political instability; changes in currency exchange rates; inefficient markets and higher transaction costs; foreign economic conditions; or inadequate or different regulatory and accounting standards.

Currency risk — The risk that the value of a portfolio's investments may be negatively affected by changes in foreign currency exchange rates.

Bank loans and other indebtedness risk — The risk that the portfolio will not receive payment of principal, interest, and other amounts due in connection with these investments and will depend primarily on the financial condition of the borrower and the lending institution.

Government and regulatory risk — The risk that governments or regulatory authorities have, from time to time, taken or considered actions that could adversely affect various sectors of the securities markets.

How has Delaware Core Bond Fund performed?

The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for the 1-, 5-, and 10-year or lifetime periods compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future. The returns reflect expense caps in effect during certain of these periods. The returns would be lower without the expense caps. You may obtain the Fund's most recently available month-end performance by calling 800 523-1918 or by visiting our website at delawareinvestments.com/performance.

The Fund is the successor to The Intermediate Fixed Income Portfolio of the Delaware Pooled® Trust pursuant to the reorganization (Reorganization) of The Intermediate Fixed Income Portfolio into the Fund, which occurred on September 30, 2009. Prior to the Reorganization, the Fund had no investment operations. Accordingly, the performance information shown below for periods prior to September 30, 2009 is historical information for The Intermediate Fixed Income Portfolio. The Intermediate Fixed Income Portfolio had the same investment objective and a similar investment strategy as the Fund, and was managed by the same portfolio managers. Because the Fund's fees and expenses are higher than those of The Intermediate Fixed Income Portfolio, the Fund's performance would have been lower than that shown below for The Intermediate Fixed Income Portfolio.

Year-by-year total return (Class A)*

As of September 30, 2012, the Fund's Class A shares had a calendar year-to-date return of 4.89%. During the periods illustrated in this bar chart, the Fund's highest quarterly return was 6.18% for the quarter ended September 30, 2009 and its lowest quarterly return was -2.30% for the quarter ended June 30, 2004. The maximum Class A sales charge of 4.50%, which is normally deducted when you purchase shares, is not reflected in the highest/lowest quarterly returns or in the bar chart. If this fee were included, the returns would be less than those shown. The average annual returns in the table below do include the sales charge.

Average annual total returns for periods ended December 31, 2011*

Average Annual Total Returns (Delaware Core Bond Fund)	Label	1 Year	5 Years	10 years or lifetime	Lifetime
Class A		3.12%	5.66%	5.07%
Class A return after taxes on distributions		1.14%	3.94%	3.36%
Class A return after taxes on distributions and sale of Fund shares		2.05%	3.81%	3.30%
Class C	(lifetime: 9/30/09-12/31/11)	6.17%			5.91%
Class R	(lifetime: 9/30/09-12/31/11)	7.06%			6.38%
Institutional Class	(lifetime: 9/30/09-12/31/11)	8.31%			7.23%
Barclays U.S. Aggregate Index (reflects no deduction for fees, expenses, or taxes)		7.84%	6.50%	5.78%

* Because the Fund has combined its retail and institutional prospectuses, the bar chart and the after tax returns in the average annual total returns table show the performance of the Fund's Class A shares.

After-tax performance is presented only for Class A shares of the Fund. The after-tax returns for other Fund classes may vary. Actual after-tax returns depend on the investor's individual tax situation and may differ from the returns shown. After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs). The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

[1] Class C shares redeemed within one year of purchase are subject to a 1.00% contingent deferred sales charge (CDSC).

[1] The Fund's investment manager, Delaware Management Company (Manager), has contractually agreed to waive all or a portion of its investment advisory fees and/or pay/reimburse expenses (excluding any 12b-1 plan, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) in order to prevent annual fund operating expenses from exceeding, in an aggregate amount, 0.65% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. In addition, the Fund's distributor, Delaware Distributors, L.P. (Distributor), has contracted to limit the Class A and Class R shares' 12b-1 fee for the Fund from November 28, 2012 through November 28, 2013 to no more than 0.25% and 0.50% of average daily net assets, respectively. These waivers and reimbursements may only be terminated by agreement of the Manager and the Fund.

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Shareholder Fees (dei_DocumentInformationDocumentAxis)	0 Months Ended
	Nov. 28, 2012
(Delaware Core Bond Fund) | Class A
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	4.50%
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none
(Delaware Core Bond Fund) | Class C
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	1.00%	[1]
(Delaware Core Bond Fund) | Institutional Class
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none
(Delaware Core Bond Fund) | Class R
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none
(Delaware Corporate Bond Fund) | Class A
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	4.50%
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none
(Delaware Corporate Bond Fund) | Class B
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	4.00%	[2]
(Delaware Corporate Bond Fund) | Class C
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	1.00%	[2]
(Delaware Corporate Bond Fund) | Institutional Class
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none
(Delaware Corporate Bond Fund) | Class R
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none
(Delaware Extended Duration Bond Fund) | Class A
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	4.50%
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none
(Delaware Extended Duration Bond Fund) | Class B
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	4.00%	[2]
(Delaware Extended Duration Bond Fund) | Class C
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	1.00%	[2]
(Delaware Extended Duration Bond Fund) | Institutional Class
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none
(Delaware Extended Duration Bond Fund) | Class R
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none
(Delaware High-Yield Opportunities Fund) | Class A
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	4.50%
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none
(Delaware High-Yield Opportunities Fund) | Class B
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	4.00%	[2]
(Delaware High-Yield Opportunities Fund) | Class C
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	1.00%	[2]
(Delaware High-Yield Opportunities Fund) | Institutional Class
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none
(Delaware High-Yield Opportunities Fund) | Class R
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none
(Delaware Diversified Floating Rate Fund) | Class A
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	2.75%
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none
(Delaware Diversified Floating Rate Fund) | Class C
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	1.00%	[1]
(Delaware Diversified Floating Rate Fund) | Institutional Class
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none
(Delaware Diversified Floating Rate Fund) | Class R
Shareholder Fees:
Maximum sales charge (load) imposed on purchases as a percentage of offering price	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none

[1] Class C shares redeemed within one year of purchase are subject to a 1.00% contingent deferred sales charge (CDSC).

[2] If you redeem Class B shares during the first year after you buy them, you will pay a contingent deferred sales charge (CDSC) of 4.00%, which declines to 3.00% during the second year, 2.25% during the third year, 1.50% during the fourth and fifth years, 1.00% during the sixth year, and 0% thereafter. Class C shares redeemed within one year of purchase are subject to a 1.00% CDSC.

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Annual Total Returns (dei_DocumentInformationDocumentAxis, Class A)	0 Months Ended
	Nov. 28, 2012
(Delaware Core Bond Fund) | Class A
Bar Chart Table:
Annual Return 2002	6.84%
Annual Return 2003	5.79%
Annual Return 2004	3.90%
Annual Return 2005	1.79%
Annual Return 2006	4.09%
Annual Return 2007	5.96%
Annual Return 2008	0.87%
Annual Return 2009	12.85%
Annual Return 2010	5.89%
Annual Return 2011	7.99%
(Delaware Corporate Bond Fund) | Class A
Bar Chart Table:
Annual Return 2002	10.84%
Annual Return 2003	12.71%
Annual Return 2004	7.07%
Annual Return 2005	1.85%
Annual Return 2006	6.60%
Annual Return 2007	3.10%
Annual Return 2008	(8.44%)
Annual Return 2009	28.84%
Annual Return 2010	11.49%
Annual Return 2011	7.31%
(Delaware Extended Duration Bond Fund) | Class A
Bar Chart Table:
Annual Return 2002	13.02%
Annual Return 2003	15.04%
Annual Return 2004	10.03%
Annual Return 2005	2.85%
Annual Return 2006	5.33%
Annual Return 2007	3.02%
Annual Return 2008	2.85%
Annual Return 2009	24.96%
Annual Return 2010	14.31%
Annual Return 2011	16.50%
(Delaware High-Yield Opportunities Fund) | Class A
Bar Chart Table:
Annual Return 2002	1.79%
Annual Return 2003	29.41%
Annual Return 2004	14.12%
Annual Return 2005	3.04%
Annual Return 2006	12.36%
Annual Return 2007	1.61%
Annual Return 2008	(25.83%)
Annual Return 2009	49.69%
Annual Return 2010	16.31%
Annual Return 2011	1.91%
(Delaware Diversified Floating Rate Fund) | Class A
Bar Chart Table:
Annual Return 2011	0.17%

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(Delaware Corporate Bond Fund)

What is the Fund's investment objective?

Delaware Corporate Bond Fund seeks to provide investors with total return.

What are the Fund's fees and expenses?

The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Shareholder fees (fees paid directly from your investment)

Shareholder Fees (Delaware Corporate Bond Fund)	Class A	Class B		Class C		Class R	Institutional Class
Maximum sales charge (load) imposed on purchases as a percentage of offering price	4.50%	none		none		none	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none	4.00%	[1]	1.00%	[1]	none	none

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses (Delaware Corporate Bond Fund)		Class A	Class B	Class C	Class R	Institutional Class
Management fees		0.48%	0.48%	0.48%	0.48%	0.48%
Distribution and service (12b-1) fees		0.30%	1.00%	1.00%	0.60%	none
Other expenses		0.23%	0.23%	0.23%	0.23%	0.23%
Total annual fund operating expenses		1.01%	1.71%	1.71%	1.31%	0.71%
Fee waivers and expense reimbursements	[1]	(0.07%)	(0.02%)	(0.02%)	(0.12%)	(0.02%)
Total annual fund operating expenses after fee waivers and expense reimbursements		0.94%	1.69%	1.69%	1.19%	0.69%

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and reflects the applicable waivers and reimbursements for the 1-year contractual period and the total operating expenses without waivers for years 2 through 10. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example (Delaware Corporate Bond Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	542	750	976	1,625
Class B	572	762	1,076	1,832
Class C	272	537	926	2,018
Class R	121	403	707	1,569
Institutional Class	70	225	393	881

Expense Example, No Redemption (Delaware Corporate Bond Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class B	172	537	926	1,832
Class C	172	537	926	2,018

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 202% of the average value of its portfolio.

What are the Fund's principal investment strategies?

The Fund invests primarily in corporate bonds. Our focus is on corporate bonds that have investment grade credit ratings from a nationally recognized statistical rating organization (NRSRO). The bonds we select for the portfolio are typically rated BBB- and above by Standard & Poor's (S&P), Baa3 and above by Moody's Investors Service, Inc. (Moody's), or similarly rated by another NRSRO. We may also invest in unrated bonds, if we believe their credit quality is comparable to those that have investment grade ratings.

The Fund may also invest up to 20% of its net assets in high yield corporate bonds ("junk bonds"). In addition, the Fund may invest up to 35% of its total assets in foreign securities, but the Fund's total non-U.S.-dollar currency exposure will be limited, in the aggregate, to no more than 25% of net assets.

The average portfolio duration of the Fund will generally vary within two years (plus or minus) of the current average duration of the Barclays U.S. Corporate Investment Grade Index, which as of October 31, 2012, was 7.25 years. Duration measures a bond's sensitivity to interest rates by indicating the approximate change in a bond or bond fund's price given a 1% change in interest rates.

Under normal circumstances, the Fund will invest at least 80% of its net assets in corporate bonds. This policy is not a fundamental investment policy and can be changed without shareholder approval. However, shareholders will be given notice at least 60 days prior to any such change.

What are the principal risks of investing in the Fund?

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio. Principal risks include:

Investments not guaranteed by the Manager or its affiliates — Investments in the Fund are not and will not be deposits with or liabilities of Macquarie Bank Limited ABN 46 008 583 542 and its holding companies, including their subsidiaries or related companies (Macquarie Group), and are subject to investment risk, including possible delays in repayment and loss of income and capital invested. No Macquarie Group company guarantees or will guarantee the performance of the Fund, the repayment of capital from the Fund, or any particular rate of return.

Market risk — The risk that all or a majority of the securities in a certain market — such as the stock or bond market — will decline in value because of factors such as adverse political or economic conditions, future expectations, investor confidence, or heavy institutional selling.

Interest rate risk — The risk that securities will decrease in value if interest rates rise. This risk is generally associated with bonds.

Credit risk — The risk that an issuer of a debt security, including a governmental issuer, may be unable to make interest payments and repay principal in a timely manner.

High yield (junk bond) risk — The risk that high yield securities, commonly known as "junk bonds," are subject to reduced creditworthiness of issuers; increased risk of default and a more limited and less liquid secondary market; and greater price volatility and risk of loss of income and principal than are higher rated securities. High yield bonds are sometimes issued by municipalities with less financial strength and therefore less ability to make projected debt payments on the bonds.

Bank loans and other indebtedness risk — The risk that the portfolio will not receive payment of principal, interest, and other amounts due in connection with these investments and will depend primarily on the financial condition of the borrower and the lending institution.

Foreign risk — The risk that foreign securities (particularly in emerging markets) may be adversely affected by political instability; changes in currency exchange rates; inefficient markets and higher transaction costs; foreign economic conditions; or inadequate or different regulatory and accounting standards.

Forward foreign currency risk — The use of forward foreign currency exchange contracts may substantially change a fund's exposure to currency exchange rates and could result in losses to the fund if currencies do not perform as the Manager expects. The use of these investments as a hedging technique to reduce a fund's exposure to currency risks may also reduce its ability to benefit from favorable changes in currency exchange rates.

Liquidity risk — The possibility that securities cannot be readily sold within seven days at approximately the price at which a fund has valued them.

Derivatives risk — Derivative contracts, such as options, futures, and swaps, may involve additional expenses (such as the payment of premiums) and are subject to significant loss if a security, or a securities index to which a derivative contract is associated, moves in the opposite direction from what the portfolio manager anticipated. Derivative contracts are also subject to the risk that the counterparty may fail to perform its obligations under the contract due to financial difficulties (such as a bankruptcy or reorganization).

Government and regulatory risk — The risk that governments or regulatory authorities have, from time to time, taken or considered actions that could adversely affect various sectors of the securities markets.

How has Delaware Corporate Bond Fund performed?

The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for the 1-, 5-, and 10-year or lifetime periods compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future. The returns reflect expense caps in effect during certain of these periods. The returns would be lower without the expense caps. You may obtain the Fund's most recently available month-end performance by calling 800 523-1918 or by visiting our website at delawareinvestments.com/performance.

Year-by-year total return (Class A)*

As of September 30, 2012, Delaware Corporate Bond Fund's Class A shares had a calendar year-to-date return of 12.02%. During the periods illustrated in this bar chart, Class A's highest quarterly return was 14.62% for the quarter ended June 30, 2009 and its lowest quarterly return was -6.83% for the quarter ended September 30, 2008. The maximum Class A sales charge of 4.50%, which is normally deducted when you purchase shares, is not reflected in the highest/lowest quarterly returns or in the bar chart. If this sales charge were included, the returns would be less than those shown. The average annual returns in the table below do include the sales charge.

Average annual total returns for periods ended December 31, 2011*

Average Annual Total Returns (Delaware Corporate Bond Fund)	Label	1 Year	5 Years	10 years or lifetime	Lifetime
Class A		2.41%	6.79%	7.27%
Class A return after taxes on distributions		0.03%	4.32%	4.88%
Class A return after taxes on distributions and sale of Fund shares		1.75%	4.35%	4.82%
Class B		2.70%	6.80%	7.12%
Class C		5.51%	6.98%	6.97%
Class R	(lifetime: 6/2/03-12/31/11)	7.04%	7.52%		6.33%
Institutional Class		7.57%	8.09%	8.04%
Barclays U.S. Corporate Investment Grade Index (reflects no deduction for fees, expenses, or taxes)		8.15%	6.82%	6.36%

* Because the Fund has combined its retail and institutional prospectuses, the bar chart and the after tax returns in the average annual total returns table show the performance of the Fund's Class A shares.

After-tax performance is presented only for Class A shares of the Fund. The after-tax returns for other Fund classes may vary. Actual after-tax returns depend on the investor's individual tax situation and may differ from the returns shown. After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs). The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

(Delaware Extended Duration Bond Fund)

What is the Fund's investment objective?

Delaware Extended Duration Bond Fund seeks to provide investors with total return.

What are the Fund's fees and expenses?

The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Shareholder fees (fees paid directly from your investment)

Shareholder Fees (Delaware Extended Duration Bond Fund)	Class A	Class B		Class C		Class R	Institutional Class
Maximum sales charge (load) imposed on purchases as a percentage of offering price	4.50%	none		none		none	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none	4.00%	[1]	1.00%	[1]	none	none

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses (Delaware Extended Duration Bond Fund)		Class A	Class B	Class C	Class R	Institutional Class
Management fees		0.54%	0.54%	0.54%	0.54%	0.54%
Distribution and service (12b-1) fees		0.30%	1.00%	1.00%	0.60%	none
Other expenses		0.22%	0.22%	0.22%	0.22%	0.22%
Total annual fund operating expenses		1.06%	1.76%	1.76%	1.36%	0.76%
Fee waivers and expense reimbursements	[1]	(0.11%)	(0.06%)	(0.06%)	(0.16%)	(0.06%)
Total annual fund operating expenses after fee waivers and expense reimbursements		0.95%	1.70%	1.70%	1.20%	0.70%

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and reflects the applicable waivers and reimbursements for the 1-year contractual period and the total operating expenses without waivers for years 2 through 10. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example (Delaware Extended Duration Bond Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	543	762	998	1,676
Class B	573	773	1,099	1,883
Class C	273	548	949	2,068
Class R	122	415	729	1,621
Institutional Class	72	237	416	937

Expense Example, No Redemption (Delaware Extended Duration Bond Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class B	173	548	949	1,883
Class C	173	548	949	2,068

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 172% of the average value of its portfolio.

What are the Fund's principal investment strategies?

The Fund invests primarily in corporate bonds. Our focus is on corporate bonds that have investment grade credit ratings from a nationally recognized statistical rating organization (NRSRO). The bonds we select for the portfolio are typically rated BBB- and above by Standard & Poor's (S&P), Baa3 and above by Moody's Investors Service, Inc. (Moody's), or similarly rated by another NRSRO. We may also invest in unrated bonds, if we believe their credit quality is comparable to those that have investment grade ratings.

The Fund may also invest up to 20% of its net assets in high yield corporate bonds ("junk bonds"). In addition, the Fund may invest up to 35% of its total assets in foreign securities, but the Fund's total non-U.S.-dollar currency exposure will be limited, in the aggregate, to no more than 25% of net assets.

The average portfolio duration of the Fund will generally vary within two years (plus or minus) of the current average duration of the Barclays Long U.S. Corporate Index, which as of October 31, 2012, was 14 years. Duration measures a bond's sensitivity to interest rates by indicating the approximate change in a bond or bond fund's price given a 1% change in interest rates.

Under normal circumstances, the Fund will invest at least 80% of its net assets in corporate bonds. This policy is not a fundamental investment policy and can be changed without shareholder approval. However, shareholders will be given notice at least 60 days prior to any such change.

What are the principal risks of investing in the Fund?

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio. Principal risks include:

Investments not guaranteed by the Manager or its affiliates — Investments in the Fund are not and will not be deposits with or liabilities of Macquarie Bank Limited ABN 46 008 583 542 and its holding companies, including their subsidiaries or related companies (Macquarie Group), and are subject to investment risk, including possible delays in repayment and loss of income and capital invested. No Macquarie Group company guarantees or will guarantee the performance of the Fund, the repayment of capital from the Fund, or any particular rate of return.

Market risk — The risk that all or a majority of the securities in a certain market — such as the stock or bond market — will decline in value because of factors such as adverse political or economic conditions, future expectations, investor confidence, or heavy institutional selling.

Interest rate risk — The risk that securities will decrease in value if interest rates rise. This risk is generally associated with bonds.

Credit risk — The risk that an issuer of a debt security, including a governmental issuer, may be unable to make interest payments and repay principal in a timely manner.

High yield (junk bond) risk — The risk that high yield securities, commonly known as "junk bonds," are subject to reduced creditworthiness of issuers; increased risk of default and a more limited and less liquid secondary market; and greater price volatility and risk of loss of income and principal than are higher rated securities. High yield bonds are sometimes issued by municipalities with less financial strength and therefore less ability to make projected debt payments on the bonds.

Bank loans and other indebtedness risk — The risk that the portfolio will not receive payment of principal, interest, and other amounts due in connection with these investments and will depend primarily on the financial condition of the borrower and the lending institution.

Foreign risk — The risk that foreign securities (particularly in emerging markets) may be adversely affected by political instability; changes in currency exchange rates; inefficient markets and higher transaction costs; foreign economic conditions; or inadequate or different regulatory and accounting standards.

Forward foreign currency risk — The use of forward foreign currency exchange contracts may substantially change a fund's exposure to currency exchange rates and could result in losses to the fund if currencies do not perform as the Manager expects. The use of these investments as a hedging technique to reduce a fund's exposure to currency risks may also reduce its ability to benefit from favorable changes in currency exchange rates.

Liquidity risk — The possibility that securities cannot be readily sold within seven days at approximately the price at which a fund has valued them.

Derivatives risk — Derivative contracts, such as options, futures, and swaps, may involve additional expenses (such as the payment of premiums) and are subject to significant loss if a security, or a securities index to which a derivative contract is associated, moves in the opposite direction from what the portfolio manager anticipated. Derivative contracts are also subject to the risk that the counterparty may fail to perform its obligations under the contract due to financial difficulties (such as a bankruptcy or reorganization).

Government and regulatory risk — The risk that governments or regulatory authorities have, from time to time, taken or considered actions that could adversely affect various sectors of the securities markets.

How has Delaware Extended Duration Bond Fund performed?

The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for the 1-, 5-, and 10-year or lifetime periods compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future. The returns reflect expense caps in effect during certain of these periods. The returns would be lower without the expense caps. You may obtain the Fund's most recently available month-end performance by calling 800 523-1918 or by visiting our website at delawareinvestments.com/performance.

Year-by-year total return (Class A)*

As of September 30, 2012, the Fund's Class A shares had a calendar year-to-date return of 13.80%. During the periods illustrated in this bar chart, Class A's highest quarterly return was 14.88% for the quarter ended June 30, 2009 and its lowest quarterly return was -8.61% for the quarter ended September 30, 2008. The maximum Class A sales charge of 4.50%, which is normally deducted when you purchase shares, is not reflected in the highest/lowest quarterly returns or in the bar chart. If this fee were included, the returns would be less than those shown. The average annual returns in the table below do include the sales charge.

Average annual total returns for periods ended December 31, 2011*

Average Annual Total Returns (Delaware Extended Duration Bond Fund)	Label	1 Year	5 Years	10 years or lifetime	Lifetime
Class A		11.22%	9.72%	9.44%
Class A return after taxes on distributions		8.14%	7.04%	6.81%
Class A return after taxes on distributions and sale of Fund shares		7.60%	6.76%	6.59%
Class B		11.66%	9.68%	9.27%
Class C		14.64%	9.92%	9.13%
Class R	(lifetime: 10/3/05-12/31/11)	16.20%	10.45%		9.15%
Institutional Class		16.81%	10.99%	10.21%
Barclays Long U.S. Corporate Index (reflects no deduction for fees, expenses, or taxes)		15.91%	8.51%	7.98%

* Because the Fund has combined its retail and institutional prospectuses, the bar chart and the after tax returns in the average annual total returns table show the performance of the Fund's Class A shares.

After-tax performance is presented only for Class A shares of the Fund. The after-tax returns for other Fund classes may vary. Actual after-tax returns depend on the investor's individual tax situation and may differ from the returns shown. After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs). The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

[1] If you redeem Class B shares during the first year after you buy them, you will pay a contingent deferred sales charge (CDSC) of 4.00%, which declines to 3.00% during the second year, 2.25% during the third year, 1.50% during the fourth and fifth years, 1.00% during the sixth year, and 0% thereafter. Class C shares redeemed within one year of purchase are subject to a 1.00% CDSC.

[1] The Fund's investment manager, Delaware Management Company (Manager), is contractually waiving its investment advisory fees and/or paying expenses (excluding any 12b-1 fees, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) to the extent necessary to prevent total annual fund operating expenses from exceeding 0.69% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. The Fund's distributor, Delaware Distributors, L.P. (Distributor), has also contracted to limit the Class A and Class R shares' 12b-1 fees from November 28, 2012 through November 28, 2013 to no more than 0.25% and 0.50% of their respective average daily net assets. These waivers and reimbursements may only be terminated by agreement of the Manager and the Distributor, as applicable, and the Fund.

[1] If you redeem Class B shares during the first year after you buy them, you will pay a contingent deferred sales charge (CDSC) of 4.00%, which declines to 3.00% during the second year, 2.25% during the third year, 1.50% during the fourth and fifth years, 1.00% during the sixth year, and 0% thereafter. Class C shares redeemed within one year of purchase are subject to a 1.00% CDSC.

[1] The Fund's investment manager, Delaware Management Company (Manager), is contractually waiving its investment advisory fees and/or paying expenses (excluding any 12b-1 fees, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) to the extent necessary to prevent total annual fund operating expenses from exceeding 0.70% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. The Fund's distributor, Delaware Distributors, L.P. (Distributor), has also contracted to limit the Class A and Class R shares' 12b-1 fees from November 28, 2012 through November 28, 2013 to no more than 0.25% and 0.50% of their respective average daily net assets. These waivers and reimbursements may only be terminated by agreement of the Manager and the Distributor, as applicable, and the Fund.

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(Delaware Core Bond Fund)

What is the Fund's investment objective?

Delaware Core Bond Fund seeks maximum long-term total return, consistent with reasonable risk.

What are the Fund's fees and expenses?

The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Shareholder fees (fees paid directly from your investment)

Shareholder Fees (Delaware Core Bond Fund)	Class A	Class C		Class R	Institutional Class
Maximum sales charge (load) imposed on purchases as a percentage of offering price	4.50%	none		none	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none	1.00%	[1]	none	none

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses (Delaware Core Bond Fund)		Class A	Class C	Class R	Institutional Class
Management fees		0.50%	0.50%	0.50%	0.50%
Distribution and service (12b-1) fees		0.30%	1.00%	0.60%	none
Other expenses		0.54%	0.54%	0.54%	0.54%
Total annual fund operating expenses		1.34%	2.04%	1.64%	1.04%
Fee waivers and expense reimbursements	[1]	(0.44%)	(0.39%)	(0.49%)	(0.39%)
Total annual fund operating expenses after fee waivers and expense reimbursements		0.90%	1.65%	1.15%	0.65%

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and reflects the applicable waivers and reimbursements for the 1-year contractual period and the total operating expenses without waivers for years 2 through 10. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example (Delaware Core Bond Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	538	814	1,111	1,953
Class C	268	602	1,062	2,338
Class R	117	469	846	1,903
Institutional Class	66	292	536	1,236

Expense Example, No Redemption (Delaware Core Bond Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class C	168	602	1,062	2,338

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 517% of the average value of its portfolio.

What are the Fund's principal investment strategies?

The Fund will invest primarily in a diversified portfolio of investment grade, fixed income obligations, including securities issued or guaranteed by the U.S. government, its agencies or instrumentalities (U.S. government securities), mortgage-backed securities, asset-backed securities, corporate bonds, and other fixed income securities.

Under normal circumstances, the Fund will invest at least 80% of its net assets in fixed income securities (80% Policy). The Fund's 80% Policy may be changed without shareholder approval. However, shareholders will be given notice at least 60 days prior to any such change.

The Fund will invest principally in debt obligations issued or guaranteed by the U.S. government and by U.S. corporations. The U.S. government securities in which the Fund may invest include a variety of securities that are issued or guaranteed as to the payment of principal and interest by the U.S. government, and by various agencies or instrumentalities that have been established or sponsored by the U.S. government. The corporate debt obligations in which the Fund may invest include, but are not limited to, bonds, notes, debentures, and commercial paper of U.S. companies.

The Fund's assets may also be invested in mortgage-backed securities issued or guaranteed by the U.S. government, its agencies or instrumentalities, or by government-sponsored corporations. Other mortgage-backed securities in which the Fund may invest are issued by certain private, nongovernment entities. Subject to quality limitations, the Fund may also invest in securities that are backed by assets such as receivables on home equity and credit card loans, automobile, mobile home, recreational vehicle and other loans, wholesale dealer floor plans, and leases.

All securities purchased by the Fund will have an investment grade rating at the time of purchase. Investment grade fixed income obligations will be those rated BBB- or higher by S&P, Baa3 or higher by Moody's, or similarly rated by another nationally recognized statistical rating organization (NRSRO), or those that are deemed to be of comparable quality. To the extent that the rating of a debt obligation held by the Fund falls below investment grade, the Fund, as soon as practicable, will dispose of the security, unless such disposal would be detrimental to the Fund in light of market conditions.

The Fund may invest up to 20% of its assets in foreign securities. The Fund intends to invest its foreign assets primarily in fixed income securities of issuers organized or having a majority of their assets or deriving a majority of their operating income in foreign countries. These fixed income securities include foreign government securities, debt obligations of foreign companies, and securities issued by supranational entities. The Fund may invest in securities issued in any currency and may hold foreign currencies. Presently, the Fund intends to invest its foreign assets primarily in U.S. dollar-denominated fixed income securities in a manner consistent with the foreign securities weighting in the Fund's benchmark, the Barclays U.S. Aggregate Index.

In unusual market conditions, in order to meet redemption requests, for temporary defensive purposes, and pending investment, the Fund may hold a substantial portion of its assets in cash or short-term fixed income obligations. Subject to certain limitations, the Fund will also be permitted to use various derivative instruments, including options, futures contracts, options on futures contracts, foreign currency transactions, interest rate swaps, and index swap agreements.

What are the principal risks of investing in the Fund?

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio. Principal risks include:

Investments not guaranteed by the Manager or its affiliates — Investments in the Fund are not and will not be deposits with or liabilities of Macquarie Bank Limited ABN 46 008 583 542 and its holding companies, including their subsidiaries or related companies (Macquarie Group), and are subject to investment risk, including possible delays in repayment and loss of income and capital invested. No Macquarie Group company guarantees or will guarantee the performance of the Fund, the repayment of capital from the Fund, or any particular rate of return.

Market risk — The risk that all or a majority of the securities in a certain market — such as the stock or bond market — will decline in value because of factors such as adverse political or economic conditions, future expectations, investor confidence, or heavy institutional selling.

Interest rate risk — The risk that securities will decrease in value if interest rates rise. This risk is generally associated with bonds.

Credit risk — The risk that an issuer of a debt security, including a governmental issuer, may be unable to make interest payments and repay principal in a timely manner.

Prepayment risk — The risk that the principal on a bond that is held by a portfolio will be prepaid prior to maturity at a time when interest rates are lower than what that bond was paying. A portfolio may then have to reinvest that money at a lower interest rate.

Liquidity risk — The possibility that securities cannot be readily sold within seven days at approximately the price at which a fund has valued them.

Derivatives risk — Derivative contracts, such as options, futures, and swaps, may involve additional expenses (such as the payment of premiums) and are subject to significant loss if a security, or a securities index to which a derivative contract is associated, moves in the opposite direction from what the portfolio manager anticipated. Derivative contracts are also subject to the risk that the counterparty may fail to perform its obligations under the contract due to financial difficulties (such as a bankruptcy or reorganization).

Foreign risk — The risk that foreign securities (particularly in emerging markets) may be adversely affected by political instability; changes in currency exchange rates; inefficient markets and higher transaction costs; foreign economic conditions; or inadequate or different regulatory and accounting standards.

Currency risk — The risk that the value of a portfolio's investments may be negatively affected by changes in foreign currency exchange rates.

Bank loans and other indebtedness risk — The risk that the portfolio will not receive payment of principal, interest, and other amounts due in connection with these investments and will depend primarily on the financial condition of the borrower and the lending institution.

Government and regulatory risk — The risk that governments or regulatory authorities have, from time to time, taken or considered actions that could adversely affect various sectors of the securities markets.

How has Delaware Core Bond Fund performed?

The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for the 1-, 5-, and 10-year or lifetime periods compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future. The returns reflect expense caps in effect during certain of these periods. The returns would be lower without the expense caps. You may obtain the Fund's most recently available month-end performance by calling 800 523-1918 or by visiting our website at delawareinvestments.com/performance.

The Fund is the successor to The Intermediate Fixed Income Portfolio of the Delaware Pooled® Trust pursuant to the reorganization (Reorganization) of The Intermediate Fixed Income Portfolio into the Fund, which occurred on September 30, 2009. Prior to the Reorganization, the Fund had no investment operations. Accordingly, the performance information shown below for periods prior to September 30, 2009 is historical information for The Intermediate Fixed Income Portfolio. The Intermediate Fixed Income Portfolio had the same investment objective and a similar investment strategy as the Fund, and was managed by the same portfolio managers. Because the Fund's fees and expenses are higher than those of The Intermediate Fixed Income Portfolio, the Fund's performance would have been lower than that shown below for The Intermediate Fixed Income Portfolio.

Year-by-year total return (Class A)*

As of September 30, 2012, the Fund's Class A shares had a calendar year-to-date return of 4.89%. During the periods illustrated in this bar chart, the Fund's highest quarterly return was 6.18% for the quarter ended September 30, 2009 and its lowest quarterly return was -2.30% for the quarter ended June 30, 2004. The maximum Class A sales charge of 4.50%, which is normally deducted when you purchase shares, is not reflected in the highest/lowest quarterly returns or in the bar chart. If this fee were included, the returns would be less than those shown. The average annual returns in the table below do include the sales charge.

Average annual total returns for periods ended December 31, 2011*

Average Annual Total Returns (Delaware Core Bond Fund)	Label	1 Year	5 Years	10 years or lifetime	Lifetime
Class A		3.12%	5.66%	5.07%
Class A return after taxes on distributions		1.14%	3.94%	3.36%
Class A return after taxes on distributions and sale of Fund shares		2.05%	3.81%	3.30%
Class C	(lifetime: 9/30/09-12/31/11)	6.17%			5.91%
Class R	(lifetime: 9/30/09-12/31/11)	7.06%			6.38%
Institutional Class	(lifetime: 9/30/09-12/31/11)	8.31%			7.23%
Barclays U.S. Aggregate Index (reflects no deduction for fees, expenses, or taxes)		7.84%	6.50%	5.78%

* Because the Fund has combined its retail and institutional prospectuses, the bar chart and the after tax returns in the average annual total returns table show the performance of the Fund's Class A shares.

After-tax performance is presented only for Class A shares of the Fund. The after-tax returns for other Fund classes may vary. Actual after-tax returns depend on the investor's individual tax situation and may differ from the returns shown. After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs). The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

(Delaware Corporate Bond Fund)

What is the Fund's investment objective?

Delaware Corporate Bond Fund seeks to provide investors with total return.

What are the Fund's fees and expenses?

The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Shareholder fees (fees paid directly from your investment)

Shareholder Fees (Delaware Corporate Bond Fund)	Class A	Class B		Class C		Class R	Institutional Class
Maximum sales charge (load) imposed on purchases as a percentage of offering price	4.50%	none		none		none	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none	4.00%	[1]	1.00%	[1]	none	none

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses (Delaware Corporate Bond Fund)		Class A	Class B	Class C	Class R	Institutional Class
Management fees		0.48%	0.48%	0.48%	0.48%	0.48%
Distribution and service (12b-1) fees		0.30%	1.00%	1.00%	0.60%	none
Other expenses		0.23%	0.23%	0.23%	0.23%	0.23%
Total annual fund operating expenses		1.01%	1.71%	1.71%	1.31%	0.71%
Fee waivers and expense reimbursements	[1]	(0.07%)	(0.02%)	(0.02%)	(0.12%)	(0.02%)
Total annual fund operating expenses after fee waivers and expense reimbursements		0.94%	1.69%	1.69%	1.19%	0.69%

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and reflects the applicable waivers and reimbursements for the 1-year contractual period and the total operating expenses without waivers for years 2 through 10. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example (Delaware Corporate Bond Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	542	750	976	1,625
Class B	572	762	1,076	1,832
Class C	272	537	926	2,018
Class R	121	403	707	1,569
Institutional Class	70	225	393	881

Expense Example, No Redemption (Delaware Corporate Bond Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class B	172	537	926	1,832
Class C	172	537	926	2,018

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 202% of the average value of its portfolio.

What are the Fund's principal investment strategies?

The Fund invests primarily in corporate bonds. Our focus is on corporate bonds that have investment grade credit ratings from a nationally recognized statistical rating organization (NRSRO). The bonds we select for the portfolio are typically rated BBB- and above by Standard & Poor's (S&P), Baa3 and above by Moody's Investors Service, Inc. (Moody's), or similarly rated by another NRSRO. We may also invest in unrated bonds, if we believe their credit quality is comparable to those that have investment grade ratings.

The Fund may also invest up to 20% of its net assets in high yield corporate bonds ("junk bonds"). In addition, the Fund may invest up to 35% of its total assets in foreign securities, but the Fund's total non-U.S.-dollar currency exposure will be limited, in the aggregate, to no more than 25% of net assets.

The average portfolio duration of the Fund will generally vary within two years (plus or minus) of the current average duration of the Barclays U.S. Corporate Investment Grade Index, which as of October 31, 2012, was 7.25 years. Duration measures a bond's sensitivity to interest rates by indicating the approximate change in a bond or bond fund's price given a 1% change in interest rates.

Under normal circumstances, the Fund will invest at least 80% of its net assets in corporate bonds. This policy is not a fundamental investment policy and can be changed without shareholder approval. However, shareholders will be given notice at least 60 days prior to any such change.

What are the principal risks of investing in the Fund?

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio. Principal risks include:

Investments not guaranteed by the Manager or its affiliates — Investments in the Fund are not and will not be deposits with or liabilities of Macquarie Bank Limited ABN 46 008 583 542 and its holding companies, including their subsidiaries or related companies (Macquarie Group), and are subject to investment risk, including possible delays in repayment and loss of income and capital invested. No Macquarie Group company guarantees or will guarantee the performance of the Fund, the repayment of capital from the Fund, or any particular rate of return.

Market risk — The risk that all or a majority of the securities in a certain market — such as the stock or bond market — will decline in value because of factors such as adverse political or economic conditions, future expectations, investor confidence, or heavy institutional selling.

Interest rate risk — The risk that securities will decrease in value if interest rates rise. This risk is generally associated with bonds.

Credit risk — The risk that an issuer of a debt security, including a governmental issuer, may be unable to make interest payments and repay principal in a timely manner.

High yield (junk bond) risk — The risk that high yield securities, commonly known as "junk bonds," are subject to reduced creditworthiness of issuers; increased risk of default and a more limited and less liquid secondary market; and greater price volatility and risk of loss of income and principal than are higher rated securities. High yield bonds are sometimes issued by municipalities with less financial strength and therefore less ability to make projected debt payments on the bonds.

Bank loans and other indebtedness risk — The risk that the portfolio will not receive payment of principal, interest, and other amounts due in connection with these investments and will depend primarily on the financial condition of the borrower and the lending institution.

Foreign risk — The risk that foreign securities (particularly in emerging markets) may be adversely affected by political instability; changes in currency exchange rates; inefficient markets and higher transaction costs; foreign economic conditions; or inadequate or different regulatory and accounting standards.

Forward foreign currency risk — The use of forward foreign currency exchange contracts may substantially change a fund's exposure to currency exchange rates and could result in losses to the fund if currencies do not perform as the Manager expects. The use of these investments as a hedging technique to reduce a fund's exposure to currency risks may also reduce its ability to benefit from favorable changes in currency exchange rates.

Liquidity risk — The possibility that securities cannot be readily sold within seven days at approximately the price at which a fund has valued them.

Derivatives risk — Derivative contracts, such as options, futures, and swaps, may involve additional expenses (such as the payment of premiums) and are subject to significant loss if a security, or a securities index to which a derivative contract is associated, moves in the opposite direction from what the portfolio manager anticipated. Derivative contracts are also subject to the risk that the counterparty may fail to perform its obligations under the contract due to financial difficulties (such as a bankruptcy or reorganization).

Government and regulatory risk — The risk that governments or regulatory authorities have, from time to time, taken or considered actions that could adversely affect various sectors of the securities markets.

How has Delaware Corporate Bond Fund performed?

The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for the 1-, 5-, and 10-year or lifetime periods compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future. The returns reflect expense caps in effect during certain of these periods. The returns would be lower without the expense caps. You may obtain the Fund's most recently available month-end performance by calling 800 523-1918 or by visiting our website at delawareinvestments.com/performance.

Year-by-year total return (Class A)*

As of September 30, 2012, Delaware Corporate Bond Fund's Class A shares had a calendar year-to-date return of 12.02%. During the periods illustrated in this bar chart, Class A's highest quarterly return was 14.62% for the quarter ended June 30, 2009 and its lowest quarterly return was -6.83% for the quarter ended September 30, 2008. The maximum Class A sales charge of 4.50%, which is normally deducted when you purchase shares, is not reflected in the highest/lowest quarterly returns or in the bar chart. If this sales charge were included, the returns would be less than those shown. The average annual returns in the table below do include the sales charge.

Average annual total returns for periods ended December 31, 2011*

Average Annual Total Returns (Delaware Corporate Bond Fund)	Label	1 Year	5 Years	10 years or lifetime	Lifetime
Class A		2.41%	6.79%	7.27%
Class A return after taxes on distributions		0.03%	4.32%	4.88%
Class A return after taxes on distributions and sale of Fund shares		1.75%	4.35%	4.82%
Class B		2.70%	6.80%	7.12%
Class C		5.51%	6.98%	6.97%
Class R	(lifetime: 6/2/03-12/31/11)	7.04%	7.52%		6.33%
Institutional Class		7.57%	8.09%	8.04%
Barclays U.S. Corporate Investment Grade Index (reflects no deduction for fees, expenses, or taxes)		8.15%	6.82%	6.36%

* Because the Fund has combined its retail and institutional prospectuses, the bar chart and the after tax returns in the average annual total returns table show the performance of the Fund's Class A shares.

After-tax performance is presented only for Class A shares of the Fund. The after-tax returns for other Fund classes may vary. Actual after-tax returns depend on the investor's individual tax situation and may differ from the returns shown. After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs). The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

(Delaware Extended Duration Bond Fund)

What is the Fund's investment objective?

Delaware Extended Duration Bond Fund seeks to provide investors with total return.

What are the Fund's fees and expenses?

The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Shareholder fees (fees paid directly from your investment)

Shareholder Fees (Delaware Extended Duration Bond Fund)	Class A	Class B		Class C		Class R	Institutional Class
Maximum sales charge (load) imposed on purchases as a percentage of offering price	4.50%	none		none		none	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none	4.00%	[1]	1.00%	[1]	none	none

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses (Delaware Extended Duration Bond Fund)		Class A	Class B	Class C	Class R	Institutional Class
Management fees		0.54%	0.54%	0.54%	0.54%	0.54%
Distribution and service (12b-1) fees		0.30%	1.00%	1.00%	0.60%	none
Other expenses		0.22%	0.22%	0.22%	0.22%	0.22%
Total annual fund operating expenses		1.06%	1.76%	1.76%	1.36%	0.76%
Fee waivers and expense reimbursements	[1]	(0.11%)	(0.06%)	(0.06%)	(0.16%)	(0.06%)
Total annual fund operating expenses after fee waivers and expense reimbursements		0.95%	1.70%	1.70%	1.20%	0.70%

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and reflects the applicable waivers and reimbursements for the 1-year contractual period and the total operating expenses without waivers for years 2 through 10. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example (Delaware Extended Duration Bond Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	543	762	998	1,676
Class B	573	773	1,099	1,883
Class C	273	548	949	2,068
Class R	122	415	729	1,621
Institutional Class	72	237	416	937

Expense Example, No Redemption (Delaware Extended Duration Bond Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class B	173	548	949	1,883
Class C	173	548	949	2,068

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 172% of the average value of its portfolio.

What are the Fund's principal investment strategies?

The Fund invests primarily in corporate bonds. Our focus is on corporate bonds that have investment grade credit ratings from a nationally recognized statistical rating organization (NRSRO). The bonds we select for the portfolio are typically rated BBB- and above by Standard & Poor's (S&P), Baa3 and above by Moody's Investors Service, Inc. (Moody's), or similarly rated by another NRSRO. We may also invest in unrated bonds, if we believe their credit quality is comparable to those that have investment grade ratings.

The Fund may also invest up to 20% of its net assets in high yield corporate bonds ("junk bonds"). In addition, the Fund may invest up to 35% of its total assets in foreign securities, but the Fund's total non-U.S.-dollar currency exposure will be limited, in the aggregate, to no more than 25% of net assets.

The average portfolio duration of the Fund will generally vary within two years (plus or minus) of the current average duration of the Barclays Long U.S. Corporate Index, which as of October 31, 2012, was 14 years. Duration measures a bond's sensitivity to interest rates by indicating the approximate change in a bond or bond fund's price given a 1% change in interest rates.

Under normal circumstances, the Fund will invest at least 80% of its net assets in corporate bonds. This policy is not a fundamental investment policy and can be changed without shareholder approval. However, shareholders will be given notice at least 60 days prior to any such change.

What are the principal risks of investing in the Fund?

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio. Principal risks include:

Investments not guaranteed by the Manager or its affiliates — Investments in the Fund are not and will not be deposits with or liabilities of Macquarie Bank Limited ABN 46 008 583 542 and its holding companies, including their subsidiaries or related companies (Macquarie Group), and are subject to investment risk, including possible delays in repayment and loss of income and capital invested. No Macquarie Group company guarantees or will guarantee the performance of the Fund, the repayment of capital from the Fund, or any particular rate of return.

Market risk — The risk that all or a majority of the securities in a certain market — such as the stock or bond market — will decline in value because of factors such as adverse political or economic conditions, future expectations, investor confidence, or heavy institutional selling.

Interest rate risk — The risk that securities will decrease in value if interest rates rise. This risk is generally associated with bonds.

Credit risk — The risk that an issuer of a debt security, including a governmental issuer, may be unable to make interest payments and repay principal in a timely manner.

High yield (junk bond) risk — The risk that high yield securities, commonly known as "junk bonds," are subject to reduced creditworthiness of issuers; increased risk of default and a more limited and less liquid secondary market; and greater price volatility and risk of loss of income and principal than are higher rated securities. High yield bonds are sometimes issued by municipalities with less financial strength and therefore less ability to make projected debt payments on the bonds.

Bank loans and other indebtedness risk — The risk that the portfolio will not receive payment of principal, interest, and other amounts due in connection with these investments and will depend primarily on the financial condition of the borrower and the lending institution.

Foreign risk — The risk that foreign securities (particularly in emerging markets) may be adversely affected by political instability; changes in currency exchange rates; inefficient markets and higher transaction costs; foreign economic conditions; or inadequate or different regulatory and accounting standards.

Forward foreign currency risk — The use of forward foreign currency exchange contracts may substantially change a fund's exposure to currency exchange rates and could result in losses to the fund if currencies do not perform as the Manager expects. The use of these investments as a hedging technique to reduce a fund's exposure to currency risks may also reduce its ability to benefit from favorable changes in currency exchange rates.

Liquidity risk — The possibility that securities cannot be readily sold within seven days at approximately the price at which a fund has valued them.

Derivatives risk — Derivative contracts, such as options, futures, and swaps, may involve additional expenses (such as the payment of premiums) and are subject to significant loss if a security, or a securities index to which a derivative contract is associated, moves in the opposite direction from what the portfolio manager anticipated. Derivative contracts are also subject to the risk that the counterparty may fail to perform its obligations under the contract due to financial difficulties (such as a bankruptcy or reorganization).

Government and regulatory risk — The risk that governments or regulatory authorities have, from time to time, taken or considered actions that could adversely affect various sectors of the securities markets.

How has Delaware Extended Duration Bond Fund performed?

The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for the 1-, 5-, and 10-year or lifetime periods compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future. The returns reflect expense caps in effect during certain of these periods. The returns would be lower without the expense caps. You may obtain the Fund's most recently available month-end performance by calling 800 523-1918 or by visiting our website at delawareinvestments.com/performance.

Year-by-year total return (Class A)*

As of September 30, 2012, the Fund's Class A shares had a calendar year-to-date return of 13.80%. During the periods illustrated in this bar chart, Class A's highest quarterly return was 14.88% for the quarter ended June 30, 2009 and its lowest quarterly return was -8.61% for the quarter ended September 30, 2008. The maximum Class A sales charge of 4.50%, which is normally deducted when you purchase shares, is not reflected in the highest/lowest quarterly returns or in the bar chart. If this fee were included, the returns would be less than those shown. The average annual returns in the table below do include the sales charge.

Average annual total returns for periods ended December 31, 2011*

Average Annual Total Returns (Delaware Extended Duration Bond Fund)	Label	1 Year	5 Years	10 years or lifetime	Lifetime
Class A		11.22%	9.72%	9.44%
Class A return after taxes on distributions		8.14%	7.04%	6.81%
Class A return after taxes on distributions and sale of Fund shares		7.60%	6.76%	6.59%
Class B		11.66%	9.68%	9.27%
Class C		14.64%	9.92%	9.13%
Class R	(lifetime: 10/3/05-12/31/11)	16.20%	10.45%		9.15%
Institutional Class		16.81%	10.99%	10.21%
Barclays Long U.S. Corporate Index (reflects no deduction for fees, expenses, or taxes)		15.91%	8.51%	7.98%

* Because the Fund has combined its retail and institutional prospectuses, the bar chart and the after tax returns in the average annual total returns table show the performance of the Fund's Class A shares.

After-tax performance is presented only for Class A shares of the Fund. The after-tax returns for other Fund classes may vary. Actual after-tax returns depend on the investor's individual tax situation and may differ from the returns shown. After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs). The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

(Delaware High-Yield Opportunities Fund)

What are the Fund's investment objectives?

Delaware High-Yield Opportunities Fund seeks total return and, as a secondary objective, high current income.

What are the Fund's fees and expenses?

The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Shareholder fees (fees paid directly from your investment)

Shareholder Fees (Delaware High-Yield Opportunities Fund)	Class A	Class B		Class C		Class R	Institutional Class
Maximum sales charge (load) imposed on purchases as a percentage of offering price	4.50%	none		none		none	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none	4.00%	[1]	1.00%	[1]	none	none

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses (Delaware High-Yield Opportunities Fund)		Class A	Class B	Class C	Class R	Institutional Class
Management fees		0.65%	0.65%	0.65%	0.65%	0.65%
Distribution and service (12b-1) fees		0.30%	1.00%	1.00%	0.60%	none
Other expenses		0.23%	0.23%	0.23%	0.23%	0.23%
Total annual fund operating expenses		1.18%	1.88%	1.88%	1.48%	0.88%
Fee waivers and expense reimbursements	[1]	(0.07%)	(0.07%)	(0.07%)	(0.17%)	(0.07%)
Total annual fund operating expenses after fee waivers and expense reimbursements		1.11%	1.81%	1.81%	1.31%	0.81%

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and reflects the applicable waivers and reimbursements for the 1-year contractual period and the total operating expenses without waivers for years 2 through 10. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example (Delaware High-Yield Opportunities Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	558	801	1,063	1,811
Class B	584	809	1,160	2,013
Class C	284	584	1,010	2,195
Class R	133	451	792	1,754
Institutional Class	83	274	481	1,078

Expense Example, No Redemption (Delaware High-Yield Opportunities Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class B	184	584	1,010	2,013
Class C	184	584	1,010	2,195

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 61% of the average value of its portfolio.

What are the Fund's principal investment strategies?

The Fund will invest primarily in corporate bonds rated BBB- or lower by Standard & Poor's (S&P), Baa3 or lower by Moody's Investors Services, Inc. (Moody's), or similarly rated by another nationally recognized statistical rating organization (NRSRO). These are commonly known as high yield bonds or junk bonds and involve greater risks than investment grade bonds. The Fund will also invest in unrated bonds we judge to be of comparable quality. Unrated bonds may be more speculative in nature than rated bonds. The Fund may also invest in U.S. and foreign government securities and corporate bonds of foreign issuers. The Fund may invest up to 25% of its total assets in foreign securities. In selecting bonds for the portfolio, we evaluate the income provided by the bond and the bond's appreciation potential as well as the issuer's ability to make income and principal payments.

Under normal circumstances, the Fund will invest at least 80% of its net assets in fixed income securities rated at the time of purchase BBB- or lower by S&P, Baa3 or lower by Moody's, or similarly rated by another NRSRO or, if unrated, judged to be of comparable quality. This policy is not a fundamental investment policy and can be changed without shareholder approval. However, shareholders will be given notice at least 60 days prior to any such change.

What are the principal risks of investing in the Fund?

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio. Principal risks include:

Investments not guaranteed by the Manager or its affiliates — Investments in the Fund are not and will not be deposits with or liabilities of Macquarie Bank Limited ABN 46 008 583 542 and its holding companies, including their subsidiaries or related companies (Macquarie Group), and are subject to investment risk, including possible delays in repayment and loss of income and capital invested. No Macquarie Group company guarantees or will guarantee the performance of the Fund, the repayment of capital from the Fund, or any particular rate of return.

Market risk — The risk that all or a majority of the securities in a certain market — such as the stock or bond market — will decline in value because of factors such as adverse political or economic conditions, future expectations, investor confidence, or heavy institutional selling.

High yield (junk bond) risk — The risk that high yield securities, commonly known as "junk bonds," are subject to reduced creditworthiness of issuers; increased risk of default and a more limited and less liquid secondary market; and greater price volatility and risk of loss of income and principal than are higher rated securities. High yield bonds are sometimes issued by municipalities with less financial strength and therefore less ability to make projected debt payments on the bonds.

Interest rate risk — The risk that securities will decrease in value if interest rates rise. This risk is generally associated with bonds.

Credit risk — The risk that an issuer of a debt security, including a governmental issuer, may be unable to make interest payments and repay principal in a timely manner.

Derivatives risk — Derivative contracts, such as options, futures and swaps, may involve additional expenses (such as the payment of premiums) and are subject to significant loss if a security, or a securities index to which a derivative contract is associated, moves in the opposite direction from what the portfolio manager anticipated.

Foreign risk — The risk that foreign securities (particularly in emerging markets) may be adversely affected by political instability; changes in currency exchange rates; inefficient markets and higher transaction costs; foreign economic conditions; or inadequate or different regulatory and accounting standards.

Bank loans and other indebtedness risk — The risk that the portfolio will not receive payment of principal, interest, and other amounts due in connection with these investments and will depend primarily on the financial condition of the borrower and the lending institution.

Liquidity risk — The possibility that securities cannot be readily sold within seven days at approximately the price at which a fund has valued them.

Valuation risk — The risk that a less liquid secondary market may make it more difficult for a fund to obtain precise valuations of certain securities in its portfolio.

Redemption risk — If investors redeem more shares of a fund than are purchased for an extended period of time, a fund may be required to sell securities without regard to the investment merits of such actions. This could decrease a fund's asset base, potentially resulting in a higher expense ratio.

Counterparty risk — The risk that a counterparty to a derivative contract (such as a swap, futures, or options contract) or a repurchase agreement may fail to perform its obligations under the contract or agreement due to financial difficulties (such as a bankruptcy or reorganization).

Government and regulatory risk — The risk that governments or regulatory authorities have, from time to time, taken or considered actions that could adversely affect various sectors of the securities markets.

How has Delaware High-Yield Opportunities Fund performed?

The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for the 1-, 5-, and 10-year or lifetime periods compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future. The returns reflect expense caps in effect during certain of these periods. The returns would be lower without the expense caps. You may obtain the Fund's most recently available month-end performance by calling 800 523-1918 or by visiting our website at delawareinvestments.com/performance.

Year-by-year total return (Class A)*

As of September 30, 2012, the Fund's Class A shares had a calendar year-to-date return of 13.52%. During the periods illustrated in this bar chart, Class A's highest quarterly return was 19.45% for the quarter ended June 30, 2009 and its lowest quarterly return was -18.08% for the quarter ended December 31, 2008. The maximum Class A sales charge of 4.50%, which is normally assessed when you purchase shares, is not reflected in the highest/lowest quarterly returns or in the bar chart. If this fee were included, the returns would be less than those shown. The average annual returns in the table below do include the sales charge.

Average annual total returns for periods ended December 31, 2011*

Average Annual Total Returns (Delaware High-Yield Opportunities Fund)	Label	1 Year	5 Years	10 years or lifetime	Lifetime
Class A		(2.79%)	5.00%	8.31%
Class A return after taxes on distributions		(5.42%)	2.00%	5.17%
Class A return after taxes on distributions and sale of Fund shares		(1.81%)	2.43%	5.21%
Class B		(2.34%)	5.03%	8.18%
Class C		0.25%	5.19%	8.03%
Class R	(lifetime: 6/2/03-12/31/11)	1.71%	5.76%		7.98%
Institutional Class		2.20%	6.29%	9.14%
BofA Merrill Lynch U.S. High Yield Constrained Index (reflects no deduction for fees, expenses, or taxes)		4.37%	7.55%	8.74%

* Because the Fund has combined its retail and institutional prospectuses, the bar chart and the after tax returns in the average annual total returns table show the performance of the Fund's Class A shares.

After-tax performance is presented only for Class A shares of the Fund. The after-tax returns for other Fund classes may vary. Actual after-tax returns depend on the investor's individual tax situation and may differ from the returns shown. After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs). The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

(Delaware Diversified Floating Rate Fund)

What is the Fund's investment objective?

Delaware Diversified Floating Rate Fund seeks total return.

What are the Fund's fees and expenses?

The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Shareholder fees (fees paid directly from your investment)

Shareholder Fees (Delaware Diversified Floating Rate Fund)	Class A	Class C		Class R	Institutional Class
Maximum sales charge (load) imposed on purchases as a percentage of offering price	2.75%	none		none	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none	1.00%	[1]	none	none

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses (Delaware Diversified Floating Rate Fund)		Class A	Class C	Class R	Institutional Class
Management fees		0.50%	0.50%	0.50%	0.50%
Distribution and service (12b-1) fees		0.30%	1.00%	0.60%	none
Other expenses		0.32%	0.32%	0.32%	0.32%
Total annual fund operating expenses		1.12%	1.82%	1.42%	0.82%
Fee waivers and expense reimbursements	[1]	(0.07%)	(0.02%)	(0.12%)	(0.02%)
Total annual fund operating expenses after fee waivers and expense reimbursements		1.05%	1.80%	1.30%	0.80%

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and reflects the applicable waivers and reimbursements for the 1-year contractual period and the total operating expenses without waivers for years 2 through 10. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example (Delaware Diversified Floating Rate Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	379	614	868	1,595
Class C	283	571	983	2,136
Class R	132	438	765	1,692
Institutional Class	82	260	453	1,012

Expense Example, No Redemption (Delaware Diversified Floating Rate Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class C	183	571	983	2,136

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 97% of the average value of its portfolio.

What are the Fund's principal investment strategies?

Under normal circumstances, the Fund will invest at least 80% of its net assets in floating-rate securities, including but not limited to, investment grade corporate bonds, bank loans, high yield bonds, nonagency mortgage-backed securities, asset-backed securities, securities issued or guaranteed by the U.S. government, municipal bonds, securities of foreign issuers in both developed and emerging markets, and may include derivative instruments that attempt to achieve a floating rate of income for the Fund when they are combined with a group of fixed-rate securities (the 80% Policy). The Manager will determine how much of the Fund's assets to allocate among the different types of securities in which the Fund may invest based on our evaluation of economic and market conditions and our assessment of the returns and potential for appreciation that can be achieved from various sectors of the fixed income market.

The instruments listed in the preceding paragraph may be variable and floating-rate fixed income securities that generally pay interest at rates that adjust whenever a specified interest rate changes and/or reset on predetermined dates (such as the last day of a month or calendar quarter). Derivative instruments may be utilized to effectively convert the fixed-rate interest payments from a group of certain Fund portfolio securities into floating-rate interest payments. The Fund may also invest in securities other than those listed above. The average portfolio duration (that is, the sensitivity to general changes in interest rates) of this Fund will generally not exceed one year.

Up to 50% of the Fund's total assets may be allocated to below-investment-grade securities within the Fund. Investments in emerging markets will, in the aggregate, be limited to no more than 15% of the Fund's total assets. We will limit non-U.S.-dollar-denominated securities to no more than 50% of net assets, but total non-U.S.-dollar currency exposure will be limited, in the aggregate, to no more than 25% of net assets. The Fund may also invest up to 50% of its total assets in a wide range of derivative instruments, including options, futures contracts, options on futures contracts, and swaps. In addition, the Fund may hold a portion of its assets in cash or cash equivalents. The Fund's 80% Policy described above may be changed without shareholder approval. However, shareholders will be given at least 60 days' notice prior to any such change.

What are the principal risks of investing in the Fund?

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio. Principal risks include:

Investments not guaranteed by the Manager or its affiliates — Investments in the Fund are not and will not be deposits with or liabilities of Macquarie Bank Limited ABN 46 008 583 542 and its holding companies, including their subsidiaries or related companies (Macquarie Group), and are subject to investment risk, including possible delays in repayment and loss of income and capital invested. No Macquarie Group company guarantees or will guarantee the performance of the Fund, the repayment of capital from the Fund, or any particular rate of return.

Market risk — The risk that all or a majority of the securities in a certain market — such as the stock or bond market — will decline in value because of factors such as adverse political or economic conditions, future expectations, investor confidence, or heavy institutional selling.

Credit risk — The risk that an issuer of a debt security, including a governmental issuer, may be unable to make interest payments and repay principal in a timely manner.

Bank loans and other indebtedness risk — The risk that the portfolio will not receive payment of principal, interest, and other amounts due in connection with these investments and will depend primarily on the financial condition of the borrower and the lending institution.

Interest rate risk — The risk that securities will decrease in value if interest rates rise. This risk is generally associated with bonds.

High yield (junk bond) risk — The risk that high yield securities, commonly known as "junk bonds," are subject to reduced creditworthiness of issuers; increased risk of default and a more limited and less liquid secondary market; and greater price volatility and risk of loss of income and principal than are higher rated securities.

Prepayment risk — The risk that the principal on a bond that is held by a portfolio will be prepaid prior to maturity at a time when interest rates are lower than what that bond was paying. A portfolio may then have to reinvest that money at a lower interest rate.

Foreign risk — The risk that foreign securities (particularly in emerging markets) may be adversely affected by political instability; changes in currency exchange rates; inefficient markets and higher transaction costs; foreign economic conditions; or inadequate or different regulatory and accounting standards.

Forward foreign currency risk — The use of forward foreign currency exchange contracts may substantially change a fund's exposure to currency exchange rates and could result in losses to the fund if currencies do not perform as the Manager expects. The use of these investments as a hedging technique to reduce a fund's exposure to currency risks may also reduce its ability to benefit from favorable changes in currency exchange rates.

Liquidity risk — The possibility that securities cannot be readily sold within seven days at approximately the price at which a fund has valued them.

Derivatives risk — Derivative contracts, such as options, futures, and swaps, may involve additional expenses (such as the payment of premiums) and are subject to significant loss if a security, or a securities index to which a derivative contract is associated, moves in the opposite direction from what the portfolio manager anticipated. Derivative contracts are also subject to the risk that the counterparty may fail to perform its obligations under the contract due to financial difficulties (such as a bankruptcy or reorganization).

Valuation risk — The risk that a less liquid secondary market may make it more difficult for a fund to obtain precise valuations of certain securities in its portfolio.

Government and regulatory risk — The risk that governments or regulatory authorities have, from time to time, taken or considered actions that could adversely affect various sectors of the securities markets.

How has Delaware Diversified Floating Rate Fund performed?

The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for the 1-year and lifetime periods compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future. The returns reflect expense caps in effect during these periods. The returns would be lower without the expense caps. You may obtain the Fund's most recently available month-end performance by calling 800 523-1918 or by visiting our website at delawareinvestments.com/performance.

Year-by-year total return (Class A)*

As of September 30, 2012, the Fund's Class A shares had a calendar year-to-date return of 4.64%. During the periods illustrated in this bar chart, Class A's highest quarterly return was 1.68% for the quarter ended September 30, 2010 and its lowest quarterly return was -2.42% for the quarter ended September 30,2011. The maximum Class A sales charge of 2.75%, which is normally deducted when you purchase shares, is not reflected in the highest/lowest quarterly returns or in the bar chart. If this sales charge were included, the returns would be less than those shown. The average annual returns in the table below do include the sales charge.

Average annual total returns for periods ended December 31, 2011*

Average Annual Total Returns (Delaware Diversified Floating Rate Fund)	1 Year	Lifetime
Class A	(2.56%)	0.07%	[1]
Class A return after taxes on distributions	(3.26%)	(0.68%)	[1]
Class A return after taxes on distributions and sale of Fund shares	(1.67%)	(0.37%)	[1]
Class C	(1.54%)	0.85%	[1]
Class R	(0.79%)	1.33%	[1]
Institutional Class	0.44%	1.86%	[1]
BofA Merrill Lynch U.S. Dollar 3-Month LIBOR Constant Maturity Index (reflects no deduction for fees, expenses, or taxes)	0.27%	0.31%	[1]

* Because the Fund has combined its retail and institutional prospectuses, the bar chart and the after tax returns in the average annual total returns table show the performance of the Fund's Class A shares.

After-tax performance is presented only for Class A shares of the Fund. The after-tax returns for other Fund classes may vary. Actual after-tax returns depend on the investor's individual tax situation and may differ from the returns shown. After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs). The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

[1] Class C shares redeemed within one year of purchase are subject to a 1.00% contingent deferred sales charge (CDSC).

[1] The Fund's investment manager, Delaware Management Company (Manager), has contractually agreed to waive all or a portion of its investment advisory fees and/or pay/reimburse expenses (excluding any 12b-1 plan, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) in order to prevent annual fund operating expenses from exceeding, in an aggregate amount, 0.65% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. In addition, the Fund's distributor, Delaware Distributors, L.P. (Distributor), has contracted to limit the Class A and Class R shares' 12b-1 fee for the Fund from November 28, 2012 through November 28, 2013 to no more than 0.25% and 0.50% of average daily net assets, respectively. These waivers and reimbursements may only be terminated by agreement of the Manager and the Fund.

[1] If you redeem Class B shares during the first year after you buy them, you will pay a contingent deferred sales charge (CDSC) of 4.00%, which declines to 3.00% during the second year, 2.25% during the third year, 1.50% during the fourth and fifth years, 1.00% during the sixth year, and 0% thereafter. Class C shares redeemed within one year of purchase are subject to a 1.00% CDSC.

[1] The Fund's investment manager, Delaware Management Company (Manager), is contractually waiving its investment advisory fees and/or paying expenses (excluding any 12b-1 fees, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) to the extent necessary to prevent total annual fund operating expenses from exceeding 0.69% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. The Fund's distributor, Delaware Distributors, L.P. (Distributor), has also contracted to limit the Class A and Class R shares' 12b-1 fees from November 28, 2012 through November 28, 2013 to no more than 0.25% and 0.50% of their respective average daily net assets. These waivers and reimbursements may only be terminated by agreement of the Manager and the Distributor, as applicable, and the Fund.

[1] If you redeem Class B shares during the first year after you buy them, you will pay a contingent deferred sales charge (CDSC) of 4.00%, which declines to 3.00% during the second year, 2.25% during the third year, 1.50% during the fourth and fifth years, 1.00% during the sixth year, and 0% thereafter. Class C shares redeemed within one year of purchase are subject to a 1.00% CDSC.

[1] The Fund's investment manager, Delaware Management Company (Manager), is contractually waiving its investment advisory fees and/or paying expenses (excluding any 12b-1 fees, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) to the extent necessary to prevent total annual fund operating expenses from exceeding 0.70% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. The Fund's distributor, Delaware Distributors, L.P. (Distributor), has also contracted to limit the Class A and Class R shares' 12b-1 fees from November 28, 2012 through November 28, 2013 to no more than 0.25% and 0.50% of their respective average daily net assets. These waivers and reimbursements may only be terminated by agreement of the Manager and the Distributor, as applicable, and the Fund.

[1] If you redeem Class B shares during the first year after you buy them, you will pay a contingent deferred sales charge (CDSC) of 4.00%, which declines to 3.00% during the second year, 2.25% during the third year, 1.50% during the fourth and fifth years, 1.00% during the sixth year, and 0% thereafter. Class C shares redeemed within one year of purchase are subject to a 1.00% CDSC.

[1] The Fund's investment manager, Delaware Management Company (Manager), is contractually waiving its investment advisory fees and/or paying expenses (excluding any 12b-1 plan, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) to the extent necessary to prevent total annual fund operating expenses from exceeding 0.81% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. The Fund's distributor, Delaware Distributors, L.P. (Distributor), has also contracted to limit the Class R shares' 12b-1 fees to no more than 0.50% of its average daily net assets from November 28, 2012 through November 28, 2013. These waivers and reimbursements may only be terminated by agreement of the Manager and the Distributor, as applicable, and the Fund. Additionally, the Fund's Class A shares are subject to a blended 12b-1 fee of 0.10% on all shares acquired prior to June 1, 1992 and 0.30% on all shares acquired on or after June 1, 1992. All Class A shares currently bear 12b-1 fees at the same rate, the blended rate based on the formula described above. This method of calculating Class A 12b-1 fees may be discontinued at the sole discretion of the Fund's Board.

[1] Class C shares redeemed within one year of purchase are subject to a 1.00% contingent deferred sales charge (CDSC).

[1] The Fund's investment manager, Delaware Management Company (Manager), has contractually agreed to waive all or a portion of its investment advisory fees and/or pay/reimburse expenses (excluding any 12b-1 plan, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) in order to prevent annual fund operating expenses from exceeding, in an aggregate amount, 0.80% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. In addition, the Fund's distributor, Delaware Distributors, L.P. (Distributor), has contracted to limit the Class A and Class R shares' 12b-1 fee for the Fund to no more than 0.25% and 0.50% of average daily net assets, respectively, from November 28, 2012 through November 28, 2013. These waivers and reimbursements may only be terminated by agreement of the Manager or Distributor, as applicable, and the Fund.

[1] Lifetime (2/26/10-12/31/11)

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(Delaware High-Yield Opportunities Fund)

What are the Fund's investment objectives?

Delaware High-Yield Opportunities Fund seeks total return and, as a secondary objective, high current income.

What are the Fund's fees and expenses?

The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Shareholder fees (fees paid directly from your investment)

Shareholder Fees (Delaware High-Yield Opportunities Fund)	Class A	Class B		Class C		Class R	Institutional Class
Maximum sales charge (load) imposed on purchases as a percentage of offering price	4.50%	none		none		none	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none	4.00%	[1]	1.00%	[1]	none	none

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses (Delaware High-Yield Opportunities Fund)		Class A	Class B	Class C	Class R	Institutional Class
Management fees		0.65%	0.65%	0.65%	0.65%	0.65%
Distribution and service (12b-1) fees		0.30%	1.00%	1.00%	0.60%	none
Other expenses		0.23%	0.23%	0.23%	0.23%	0.23%
Total annual fund operating expenses		1.18%	1.88%	1.88%	1.48%	0.88%
Fee waivers and expense reimbursements	[1]	(0.07%)	(0.07%)	(0.07%)	(0.17%)	(0.07%)
Total annual fund operating expenses after fee waivers and expense reimbursements		1.11%	1.81%	1.81%	1.31%	0.81%

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and reflects the applicable waivers and reimbursements for the 1-year contractual period and the total operating expenses without waivers for years 2 through 10. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example (Delaware High-Yield Opportunities Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	558	801	1,063	1,811
Class B	584	809	1,160	2,013
Class C	284	584	1,010	2,195
Class R	133	451	792	1,754
Institutional Class	83	274	481	1,078

Expense Example, No Redemption (Delaware High-Yield Opportunities Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class B	184	584	1,010	2,013
Class C	184	584	1,010	2,195

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 61% of the average value of its portfolio.

What are the Fund's principal investment strategies?

The Fund will invest primarily in corporate bonds rated BBB- or lower by Standard & Poor's (S&P), Baa3 or lower by Moody's Investors Services, Inc. (Moody's), or similarly rated by another nationally recognized statistical rating organization (NRSRO). These are commonly known as high yield bonds or junk bonds and involve greater risks than investment grade bonds. The Fund will also invest in unrated bonds we judge to be of comparable quality. Unrated bonds may be more speculative in nature than rated bonds. The Fund may also invest in U.S. and foreign government securities and corporate bonds of foreign issuers. The Fund may invest up to 25% of its total assets in foreign securities. In selecting bonds for the portfolio, we evaluate the income provided by the bond and the bond's appreciation potential as well as the issuer's ability to make income and principal payments.

Under normal circumstances, the Fund will invest at least 80% of its net assets in fixed income securities rated at the time of purchase BBB- or lower by S&P, Baa3 or lower by Moody's, or similarly rated by another NRSRO or, if unrated, judged to be of comparable quality. This policy is not a fundamental investment policy and can be changed without shareholder approval. However, shareholders will be given notice at least 60 days prior to any such change.

What are the principal risks of investing in the Fund?

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio. Principal risks include:

Investments not guaranteed by the Manager or its affiliates — Investments in the Fund are not and will not be deposits with or liabilities of Macquarie Bank Limited ABN 46 008 583 542 and its holding companies, including their subsidiaries or related companies (Macquarie Group), and are subject to investment risk, including possible delays in repayment and loss of income and capital invested. No Macquarie Group company guarantees or will guarantee the performance of the Fund, the repayment of capital from the Fund, or any particular rate of return.

Market risk — The risk that all or a majority of the securities in a certain market — such as the stock or bond market — will decline in value because of factors such as adverse political or economic conditions, future expectations, investor confidence, or heavy institutional selling.

High yield (junk bond) risk — The risk that high yield securities, commonly known as "junk bonds," are subject to reduced creditworthiness of issuers; increased risk of default and a more limited and less liquid secondary market; and greater price volatility and risk of loss of income and principal than are higher rated securities. High yield bonds are sometimes issued by municipalities with less financial strength and therefore less ability to make projected debt payments on the bonds.

Interest rate risk — The risk that securities will decrease in value if interest rates rise. This risk is generally associated with bonds.

Credit risk — The risk that an issuer of a debt security, including a governmental issuer, may be unable to make interest payments and repay principal in a timely manner.

Derivatives risk — Derivative contracts, such as options, futures and swaps, may involve additional expenses (such as the payment of premiums) and are subject to significant loss if a security, or a securities index to which a derivative contract is associated, moves in the opposite direction from what the portfolio manager anticipated.

Foreign risk — The risk that foreign securities (particularly in emerging markets) may be adversely affected by political instability; changes in currency exchange rates; inefficient markets and higher transaction costs; foreign economic conditions; or inadequate or different regulatory and accounting standards.

Bank loans and other indebtedness risk — The risk that the portfolio will not receive payment of principal, interest, and other amounts due in connection with these investments and will depend primarily on the financial condition of the borrower and the lending institution.

Liquidity risk — The possibility that securities cannot be readily sold within seven days at approximately the price at which a fund has valued them.

Valuation risk — The risk that a less liquid secondary market may make it more difficult for a fund to obtain precise valuations of certain securities in its portfolio.

Redemption risk — If investors redeem more shares of a fund than are purchased for an extended period of time, a fund may be required to sell securities without regard to the investment merits of such actions. This could decrease a fund's asset base, potentially resulting in a higher expense ratio.

Counterparty risk — The risk that a counterparty to a derivative contract (such as a swap, futures, or options contract) or a repurchase agreement may fail to perform its obligations under the contract or agreement due to financial difficulties (such as a bankruptcy or reorganization).

Government and regulatory risk — The risk that governments or regulatory authorities have, from time to time, taken or considered actions that could adversely affect various sectors of the securities markets.

How has Delaware High-Yield Opportunities Fund performed?

The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for the 1-, 5-, and 10-year or lifetime periods compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future. The returns reflect expense caps in effect during certain of these periods. The returns would be lower without the expense caps. You may obtain the Fund's most recently available month-end performance by calling 800 523-1918 or by visiting our website at delawareinvestments.com/performance.

Year-by-year total return (Class A)*

As of September 30, 2012, the Fund's Class A shares had a calendar year-to-date return of 13.52%. During the periods illustrated in this bar chart, Class A's highest quarterly return was 19.45% for the quarter ended June 30, 2009 and its lowest quarterly return was -18.08% for the quarter ended December 31, 2008. The maximum Class A sales charge of 4.50%, which is normally assessed when you purchase shares, is not reflected in the highest/lowest quarterly returns or in the bar chart. If this fee were included, the returns would be less than those shown. The average annual returns in the table below do include the sales charge.

Average annual total returns for periods ended December 31, 2011*

Average Annual Total Returns (Delaware High-Yield Opportunities Fund)	Label	1 Year	5 Years	10 years or lifetime	Lifetime
Class A		(2.79%)	5.00%	8.31%
Class A return after taxes on distributions		(5.42%)	2.00%	5.17%
Class A return after taxes on distributions and sale of Fund shares		(1.81%)	2.43%	5.21%
Class B		(2.34%)	5.03%	8.18%
Class C		0.25%	5.19%	8.03%
Class R	(lifetime: 6/2/03-12/31/11)	1.71%	5.76%		7.98%
Institutional Class		2.20%	6.29%	9.14%
BofA Merrill Lynch U.S. High Yield Constrained Index (reflects no deduction for fees, expenses, or taxes)		4.37%	7.55%	8.74%

* Because the Fund has combined its retail and institutional prospectuses, the bar chart and the after tax returns in the average annual total returns table show the performance of the Fund's Class A shares.

After-tax performance is presented only for Class A shares of the Fund. The after-tax returns for other Fund classes may vary. Actual after-tax returns depend on the investor's individual tax situation and may differ from the returns shown. After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs). The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

[1] If you redeem Class B shares during the first year after you buy them, you will pay a contingent deferred sales charge (CDSC) of 4.00%, which declines to 3.00% during the second year, 2.25% during the third year, 1.50% during the fourth and fifth years, 1.00% during the sixth year, and 0% thereafter. Class C shares redeemed within one year of purchase are subject to a 1.00% CDSC.

[1] The Fund's investment manager, Delaware Management Company (Manager), is contractually waiving its investment advisory fees and/or paying expenses (excluding any 12b-1 plan, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) to the extent necessary to prevent total annual fund operating expenses from exceeding 0.81% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. The Fund's distributor, Delaware Distributors, L.P. (Distributor), has also contracted to limit the Class R shares' 12b-1 fees to no more than 0.50% of its average daily net assets from November 28, 2012 through November 28, 2013. These waivers and reimbursements may only be terminated by agreement of the Manager and the Distributor, as applicable, and the Fund. Additionally, the Fund's Class A shares are subject to a blended 12b-1 fee of 0.10% on all shares acquired prior to June 1, 1992 and 0.30% on all shares acquired on or after June 1, 1992. All Class A shares currently bear 12b-1 fees at the same rate, the blended rate based on the formula described above. This method of calculating Class A 12b-1 fees may be discontinued at the sole discretion of the Fund's Board.

XML

Annual Fund Operating Expenses (dei_DocumentInformationDocumentAxis)	0 Months Ended
	Nov. 28, 2012
(Delaware Core Bond Fund) | Class A
Operating Expenses:
Management fees	0.50%
Distribution and service (12b-1) fees	0.30%
Other expenses	0.54%
Total annual fund operating expenses	1.34%
Fee waivers and expense reimbursements	(0.44%)	[1]
Total annual fund operating expenses after fee waivers and expense reimbursements	0.90%
(Delaware Core Bond Fund) | Class C
Operating Expenses:
Management fees	0.50%
Distribution and service (12b-1) fees	1.00%
Other expenses	0.54%
Total annual fund operating expenses	2.04%
Fee waivers and expense reimbursements	(0.39%)	[1]
Total annual fund operating expenses after fee waivers and expense reimbursements	1.65%
(Delaware Core Bond Fund) | Institutional Class
Operating Expenses:
Management fees	0.50%
Distribution and service (12b-1) fees	none
Other expenses	0.54%
Total annual fund operating expenses	1.04%
Fee waivers and expense reimbursements	(0.39%)	[1]
Total annual fund operating expenses after fee waivers and expense reimbursements	0.65%
(Delaware Core Bond Fund) | Class R
Operating Expenses:
Management fees	0.50%
Distribution and service (12b-1) fees	0.60%
Other expenses	0.54%
Total annual fund operating expenses	1.64%
Fee waivers and expense reimbursements	(0.49%)	[1]
Total annual fund operating expenses after fee waivers and expense reimbursements	1.15%
(Delaware Corporate Bond Fund) | Class A
Operating Expenses:
Management fees	0.48%
Distribution and service (12b-1) fees	0.30%
Other expenses	0.23%
Total annual fund operating expenses	1.01%
Fee waivers and expense reimbursements	(0.07%)	[2]
Total annual fund operating expenses after fee waivers and expense reimbursements	0.94%
(Delaware Corporate Bond Fund) | Class B
Operating Expenses:
Management fees	0.48%
Distribution and service (12b-1) fees	1.00%
Other expenses	0.23%
Total annual fund operating expenses	1.71%
Fee waivers and expense reimbursements	(0.02%)	[2]
Total annual fund operating expenses after fee waivers and expense reimbursements	1.69%
(Delaware Corporate Bond Fund) | Class C
Operating Expenses:
Management fees	0.48%
Distribution and service (12b-1) fees	1.00%
Other expenses	0.23%
Total annual fund operating expenses	1.71%
Fee waivers and expense reimbursements	(0.02%)	[2]
Total annual fund operating expenses after fee waivers and expense reimbursements	1.69%
(Delaware Corporate Bond Fund) | Institutional Class
Operating Expenses:
Management fees	0.48%
Distribution and service (12b-1) fees	none
Other expenses	0.23%
Total annual fund operating expenses	0.71%
Fee waivers and expense reimbursements	(0.02%)	[2]
Total annual fund operating expenses after fee waivers and expense reimbursements	0.69%
(Delaware Corporate Bond Fund) | Class R
Operating Expenses:
Management fees	0.48%
Distribution and service (12b-1) fees	0.60%
Other expenses	0.23%
Total annual fund operating expenses	1.31%
Fee waivers and expense reimbursements	(0.12%)	[2]
Total annual fund operating expenses after fee waivers and expense reimbursements	1.19%
(Delaware Extended Duration Bond Fund) | Class A
Operating Expenses:
Management fees	0.54%
Distribution and service (12b-1) fees	0.30%
Other expenses	0.22%
Total annual fund operating expenses	1.06%
Fee waivers and expense reimbursements	(0.11%)	[3]
Total annual fund operating expenses after fee waivers and expense reimbursements	0.95%
(Delaware Extended Duration Bond Fund) | Class B
Operating Expenses:
Management fees	0.54%
Distribution and service (12b-1) fees	1.00%
Other expenses	0.22%
Total annual fund operating expenses	1.76%
Fee waivers and expense reimbursements	(0.06%)	[3]
Total annual fund operating expenses after fee waivers and expense reimbursements	1.70%
(Delaware Extended Duration Bond Fund) | Class C
Operating Expenses:
Management fees	0.54%
Distribution and service (12b-1) fees	1.00%
Other expenses	0.22%
Total annual fund operating expenses	1.76%
Fee waivers and expense reimbursements	(0.06%)	[3]
Total annual fund operating expenses after fee waivers and expense reimbursements	1.70%
(Delaware Extended Duration Bond Fund) | Institutional Class
Operating Expenses:
Management fees	0.54%
Distribution and service (12b-1) fees	none
Other expenses	0.22%
Total annual fund operating expenses	0.76%
Fee waivers and expense reimbursements	(0.06%)	[3]
Total annual fund operating expenses after fee waivers and expense reimbursements	0.70%
(Delaware Extended Duration Bond Fund) | Class R
Operating Expenses:
Management fees	0.54%
Distribution and service (12b-1) fees	0.60%
Other expenses	0.22%
Total annual fund operating expenses	1.36%
Fee waivers and expense reimbursements	(0.16%)	[3]
Total annual fund operating expenses after fee waivers and expense reimbursements	1.20%
(Delaware High-Yield Opportunities Fund) | Class A
Operating Expenses:
Management fees	0.65%
Distribution and service (12b-1) fees	0.30%
Other expenses	0.23%
Total annual fund operating expenses	1.18%
Fee waivers and expense reimbursements	(0.07%)	[4]
Total annual fund operating expenses after fee waivers and expense reimbursements	1.11%
(Delaware High-Yield Opportunities Fund) | Class B
Operating Expenses:
Management fees	0.65%
Distribution and service (12b-1) fees	1.00%
Other expenses	0.23%
Total annual fund operating expenses	1.88%
Fee waivers and expense reimbursements	(0.07%)	[4]
Total annual fund operating expenses after fee waivers and expense reimbursements	1.81%
(Delaware High-Yield Opportunities Fund) | Class C
Operating Expenses:
Management fees	0.65%
Distribution and service (12b-1) fees	1.00%
Other expenses	0.23%
Total annual fund operating expenses	1.88%
Fee waivers and expense reimbursements	(0.07%)	[4]
Total annual fund operating expenses after fee waivers and expense reimbursements	1.81%
(Delaware High-Yield Opportunities Fund) | Institutional Class
Operating Expenses:
Management fees	0.65%
Distribution and service (12b-1) fees	none
Other expenses	0.23%
Total annual fund operating expenses	0.88%
Fee waivers and expense reimbursements	(0.07%)	[4]
Total annual fund operating expenses after fee waivers and expense reimbursements	0.81%
(Delaware High-Yield Opportunities Fund) | Class R
Operating Expenses:
Management fees	0.65%
Distribution and service (12b-1) fees	0.60%
Other expenses	0.23%
Total annual fund operating expenses	1.48%
Fee waivers and expense reimbursements	(0.17%)	[4]
Total annual fund operating expenses after fee waivers and expense reimbursements	1.31%
(Delaware Diversified Floating Rate Fund) | Class A
Operating Expenses:
Management fees	0.50%
Distribution and service (12b-1) fees	0.30%
Other expenses	0.32%
Total annual fund operating expenses	1.12%
Fee waivers and expense reimbursements	(0.07%)	[5]
Total annual fund operating expenses after fee waivers and expense reimbursements	1.05%
(Delaware Diversified Floating Rate Fund) | Class C
Operating Expenses:
Management fees	0.50%
Distribution and service (12b-1) fees	1.00%
Other expenses	0.32%
Total annual fund operating expenses	1.82%
Fee waivers and expense reimbursements	(0.02%)	[5]
Total annual fund operating expenses after fee waivers and expense reimbursements	1.80%
(Delaware Diversified Floating Rate Fund) | Institutional Class
Operating Expenses:
Management fees	0.50%
Distribution and service (12b-1) fees	none
Other expenses	0.32%
Total annual fund operating expenses	0.82%
Fee waivers and expense reimbursements	(0.02%)	[5]
Total annual fund operating expenses after fee waivers and expense reimbursements	0.80%
(Delaware Diversified Floating Rate Fund) | Class R
Operating Expenses:
Management fees	0.50%
Distribution and service (12b-1) fees	0.60%
Other expenses	0.32%
Total annual fund operating expenses	1.42%
Fee waivers and expense reimbursements	(0.12%)	[5]
Total annual fund operating expenses after fee waivers and expense reimbursements	1.30%

[1] The Fund's investment manager, Delaware Management Company (Manager), has contractually agreed to waive all or a portion of its investment advisory fees and/or pay/reimburse expenses (excluding any 12b-1 plan, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) in order to prevent annual fund operating expenses from exceeding, in an aggregate amount, 0.65% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. In addition, the Fund's distributor, Delaware Distributors, L.P. (Distributor), has contracted to limit the Class A and Class R shares' 12b-1 fee for the Fund from November 28, 2012 through November 28, 2013 to no more than 0.25% and 0.50% of average daily net assets, respectively. These waivers and reimbursements may only be terminated by agreement of the Manager and the Fund.

[2] The Fund's investment manager, Delaware Management Company (Manager), is contractually waiving its investment advisory fees and/or paying expenses (excluding any 12b-1 fees, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) to the extent necessary to prevent total annual fund operating expenses from exceeding 0.69% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. The Fund's distributor, Delaware Distributors, L.P. (Distributor), has also contracted to limit the Class A and Class R shares' 12b-1 fees from November 28, 2012 through November 28, 2013 to no more than 0.25% and 0.50% of their respective average daily net assets. These waivers and reimbursements may only be terminated by agreement of the Manager and the Distributor, as applicable, and the Fund.

[3] The Fund's investment manager, Delaware Management Company (Manager), is contractually waiving its investment advisory fees and/or paying expenses (excluding any 12b-1 fees, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) to the extent necessary to prevent total annual fund operating expenses from exceeding 0.70% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. The Fund's distributor, Delaware Distributors, L.P. (Distributor), has also contracted to limit the Class A and Class R shares' 12b-1 fees from November 28, 2012 through November 28, 2013 to no more than 0.25% and 0.50% of their respective average daily net assets. These waivers and reimbursements may only be terminated by agreement of the Manager and the Distributor, as applicable, and the Fund.

[4] The Fund's investment manager, Delaware Management Company (Manager), is contractually waiving its investment advisory fees and/or paying expenses (excluding any 12b-1 plan, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) to the extent necessary to prevent total annual fund operating expenses from exceeding 0.81% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. The Fund's distributor, Delaware Distributors, L.P. (Distributor), has also contracted to limit the Class R shares' 12b-1 fees to no more than 0.50% of its average daily net assets from November 28, 2012 through November 28, 2013. These waivers and reimbursements may only be terminated by agreement of the Manager and the Distributor, as applicable, and the Fund. Additionally, the Fund's Class A shares are subject to a blended 12b-1 fee of 0.10% on all shares acquired prior to June 1, 1992 and 0.30% on all shares acquired on or after June 1, 1992. All Class A shares currently bear 12b-1 fees at the same rate, the blended rate based on the formula described above. This method of calculating Class A 12b-1 fees may be discontinued at the sole discretion of the Fund's Board.

[5] The Fund's investment manager, Delaware Management Company (Manager), has contractually agreed to waive all or a portion of its investment advisory fees and/or pay/reimburse expenses (excluding any 12b-1 plan, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) in order to prevent annual fund operating expenses from exceeding, in an aggregate amount, 0.80% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. In addition, the Fund's distributor, Delaware Distributors, L.P. (Distributor), has contracted to limit the Class A and Class R shares' 12b-1 fee for the Fund to no more than 0.25% and 0.50% of average daily net assets, respectively, from November 28, 2012 through November 28, 2013. These waivers and reimbursements may only be terminated by agreement of the Manager or Distributor, as applicable, and the Fund.

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Document Type

dei_DocumentType

485BPOS

Document Period End Date

dei_DocumentPeriodEndDate

Jul. 31, 2012

Registrant Name

dei_EntityRegistrantName

DELAWARE GROUP INCOME FUNDS

Central Index Key

dei_EntityCentralIndexKey

0000027825

Amendment Flag

dei_AmendmentFlag

false

Document Creation Date

dei_DocumentCreationDate

Nov. 28, 2012

Document Effective Date

dei_DocumentEffectiveDate

Nov. 28, 2012

Prospectus Date

rr_ProspectusDate

Nov. 28, 2012

(Delaware Core Bond Fund)

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

What is the Fund's investment objective?

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

Delaware Core Bond Fund seeks maximum long-term total return, consistent with reasonable risk.

Expense [Heading]

rr_ExpenseHeading

What are the Fund's fees and expenses?

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 517% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

517.00%

Expense Breakpoint Discounts [Text]

rr_ExpenseBreakpointDiscounts

You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

100,000

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and reflects the applicable waivers and reimbursements for the 1-year contractual period and the total operating expenses without waivers for years 2 through 10. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

What are the Fund's principal investment strategies?

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund will invest primarily in a diversified portfolio of investment grade, fixed income obligations, including securities issued or guaranteed by the U.S. government, its agencies or instrumentalities (U.S. government securities), mortgage-backed securities, asset-backed securities, corporate bonds, and other fixed income securities.

Under normal circumstances, the Fund will invest at least 80% of its net assets in fixed income securities (80% Policy). The Fund's 80% Policy may be changed without shareholder approval. However, shareholders will be given notice at least 60 days prior to any such change.

The Fund will invest principally in debt obligations issued or guaranteed by the U.S. government and by U.S. corporations. The U.S. government securities in which the Fund may invest include a variety of securities that are issued or guaranteed as to the payment of principal and interest by the U.S. government, and by various agencies or instrumentalities that have been established or sponsored by the U.S. government. The corporate debt obligations in which the Fund may invest include, but are not limited to, bonds, notes, debentures, and commercial paper of U.S. companies.

The Fund's assets may also be invested in mortgage-backed securities issued or guaranteed by the U.S. government, its agencies or instrumentalities, or by government-sponsored corporations. Other mortgage-backed securities in which the Fund may invest are issued by certain private, nongovernment entities. Subject to quality limitations, the Fund may also invest in securities that are backed by assets such as receivables on home equity and credit card loans, automobile, mobile home, recreational vehicle and other loans, wholesale dealer floor plans, and leases.

All securities purchased by the Fund will have an investment grade rating at the time of purchase. Investment grade fixed income obligations will be those rated BBB- or higher by S&P, Baa3 or higher by Moody's, or similarly rated by another nationally recognized statistical rating organization (NRSRO), or those that are deemed to be of comparable quality. To the extent that the rating of a debt obligation held by the Fund falls below investment grade, the Fund, as soon as practicable, will dispose of the security, unless such disposal would be detrimental to the Fund in light of market conditions.

The Fund may invest up to 20% of its assets in foreign securities. The Fund intends to invest its foreign assets primarily in fixed income securities of issuers organized or having a majority of their assets or deriving a majority of their operating income in foreign countries. These fixed income securities include foreign government securities, debt obligations of foreign companies, and securities issued by supranational entities. The Fund may invest in securities issued in any currency and may hold foreign currencies. Presently, the Fund intends to invest its foreign assets primarily in U.S. dollar-denominated fixed income securities in a manner consistent with the foreign securities weighting in the Fund's benchmark, the Barclays U.S. Aggregate Index.

In unusual market conditions, in order to meet redemption requests, for temporary defensive purposes, and pending investment, the Fund may hold a substantial portion of its assets in cash or short-term fixed income obligations. Subject to certain limitations, the Fund will also be permitted to use various derivative instruments, including options, futures contracts, options on futures contracts, foreign currency transactions, interest rate swaps, and index swap agreements.

Risk [Heading]

rr_RiskHeading

What are the principal risks of investing in the Fund?

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio. Principal risks include:

Investments not guaranteed by the Manager or its affiliates — Investments in the Fund are not and will not be deposits with or liabilities of Macquarie Bank Limited ABN 46 008 583 542 and its holding companies, including their subsidiaries or related companies (Macquarie Group), and are subject to investment risk, including possible delays in repayment and loss of income and capital invested. No Macquarie Group company guarantees or will guarantee the performance of the Fund, the repayment of capital from the Fund, or any particular rate of return.

Market risk — The risk that all or a majority of the securities in a certain market — such as the stock or bond market — will decline in value because of factors such as adverse political or economic conditions, future expectations, investor confidence, or heavy institutional selling.

Interest rate risk — The risk that securities will decrease in value if interest rates rise. This risk is generally associated with bonds.

Credit risk — The risk that an issuer of a debt security, including a governmental issuer, may be unable to make interest payments and repay principal in a timely manner.

Prepayment risk — The risk that the principal on a bond that is held by a portfolio will be prepaid prior to maturity at a time when interest rates are lower than what that bond was paying. A portfolio may then have to reinvest that money at a lower interest rate.

Liquidity risk — The possibility that securities cannot be readily sold within seven days at approximately the price at which a fund has valued them.

Derivatives risk — Derivative contracts, such as options, futures, and swaps, may involve additional expenses (such as the payment of premiums) and are subject to significant loss if a security, or a securities index to which a derivative contract is associated, moves in the opposite direction from what the portfolio manager anticipated. Derivative contracts are also subject to the risk that the counterparty may fail to perform its obligations under the contract due to financial difficulties (such as a bankruptcy or reorganization).

Foreign risk — The risk that foreign securities (particularly in emerging markets) may be adversely affected by political instability; changes in currency exchange rates; inefficient markets and higher transaction costs; foreign economic conditions; or inadequate or different regulatory and accounting standards.

Currency risk — The risk that the value of a portfolio's investments may be negatively affected by changes in foreign currency exchange rates.

Bank loans and other indebtedness risk — The risk that the portfolio will not receive payment of principal, interest, and other amounts due in connection with these investments and will depend primarily on the financial condition of the borrower and the lending institution.

Government and regulatory risk — The risk that governments or regulatory authorities have, from time to time, taken or considered actions that could adversely affect various sectors of the securities markets.

Risk Lose Money [Text]

rr_RiskLoseMoney

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

How has Delaware Core Bond Fund performed?

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for the 1-, 5-, and 10-year or lifetime periods compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future. The returns reflect expense caps in effect during certain of these periods. The returns would be lower without the expense caps. You may obtain the Fund's most recently available month-end performance by calling 800 523-1918 or by visiting our website at delawareinvestments.com/performance.

The Fund is the successor to The Intermediate Fixed Income Portfolio of the Delaware Pooled® Trust pursuant to the reorganization (Reorganization) of The Intermediate Fixed Income Portfolio into the Fund, which occurred on September 30, 2009. Prior to the Reorganization, the Fund had no investment operations. Accordingly, the performance information shown below for periods prior to September 30, 2009 is historical information for The Intermediate Fixed Income Portfolio. The Intermediate Fixed Income Portfolio had the same investment objective and a similar investment strategy as the Fund, and was managed by the same portfolio managers. Because the Fund's fees and expenses are higher than those of The Intermediate Fixed Income Portfolio, the Fund's performance would have been lower than that shown below for The Intermediate Fixed Income Portfolio.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800 523-1918

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

delawareinvestments.com/performance

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

Year-by-year total return (Class A)*

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

As of September 30, 2012, the Fund's Class A shares had a calendar year-to-date return of 4.89%. During the periods illustrated in this bar chart, the Fund's highest quarterly return was 6.18% for the quarter ended September 30, 2009 and its lowest quarterly return was -2.30% for the quarter ended June 30, 2004. The maximum Class A sales charge of 4.50%, which is normally deducted when you purchase shares, is not reflected in the highest/lowest quarterly returns or in the bar chart. If this fee were included, the returns would be less than those shown. The average annual returns in the table below do include the sales charge.

Performance Table Heading

rr_PerformanceTableHeading

Average annual total returns for periods ended December 31, 2011*

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is presented only for Class A shares of the Fund.

Performance Table Footnotes

rr_PerformanceTableFootnotesTextBlock

* Because the Fund has combined its retail and institutional prospectuses, the bar chart and the after tax returns in the average annual total returns table show the performance of the Fund's Class A shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

After-tax performance is presented only for Class A shares of the Fund. The after-tax returns for other Fund classes may vary. Actual after-tax returns depend on the investor's individual tax situation and may differ from the returns shown. After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs). The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

(Delaware Core Bond Fund) | Barclays U.S. Aggregate Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

7.84%

5 Years

rr_AverageAnnualReturnYear05

6.50%

10 years or lifetime

rr_AverageAnnualReturnYear10

5.78%

(Delaware Core Bond Fund) | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

4.50%

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Management fees

rr_ManagementFeesOverAssets

0.50%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.30%

Other expenses

rr_OtherExpensesOverAssets

0.54%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.34%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.44%)

^[3]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

0.90%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

538

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

814

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,111

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,953

Annual Return 2002

rr_AnnualReturn2002

6.84%

Annual Return 2003

rr_AnnualReturn2003

5.79%

Annual Return 2004

rr_AnnualReturn2004

3.90%

Annual Return 2005

rr_AnnualReturn2005

1.79%

Annual Return 2006

rr_AnnualReturn2006

4.09%

Annual Return 2007

rr_AnnualReturn2007

5.96%

Annual Return 2008

rr_AnnualReturn2008

0.87%

Annual Return 2009

rr_AnnualReturn2009

12.85%

Annual Return 2010

rr_AnnualReturn2010

5.89%

Annual Return 2011

rr_AnnualReturn2011

7.99%

Year to Date Return, Label

rr_YearToDateReturnLabel

As of September 30, 2012, the Fund's Class A shares had a calendar year-to-date return of 4.89%

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Sep. 30, 2012

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

4.89%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

highest quarterly return was 6.18% for the quarter ended September 30, 2009

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

6.18%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

lowest quarterly return was -2.30% for the quarter ended June 30, 2004

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Jun. 30, 2004

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(2.30%)

1 Year

rr_AverageAnnualReturnYear01

3.12%

5 Years

rr_AverageAnnualReturnYear05

5.66%

10 years or lifetime

rr_AverageAnnualReturnYear10

5.07%

(Delaware Core Bond Fund) | Class A | return after taxes on distributions

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

1.14%

5 Years

rr_AverageAnnualReturnYear05

3.94%

10 years or lifetime

rr_AverageAnnualReturnYear10

3.36%

(Delaware Core Bond Fund) | Class A | return after taxes on distributions and sale of Fund shares

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

2.05%

5 Years

rr_AverageAnnualReturnYear05

3.81%

10 years or lifetime

rr_AverageAnnualReturnYear10

3.30%

(Delaware Core Bond Fund) | Class C

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

1.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

0.50%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.54%

Total annual fund operating expenses

rr_ExpensesOverAssets

2.04%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.39%)

^[3]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

1.65%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

268

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

602

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,062

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,338

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

168

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

602

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

1,062

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

2,338

Label

rr_AverageAnnualReturnLabel

(lifetime: 9/30/09-12/31/11)

1 Year

rr_AverageAnnualReturnYear01

6.17%

5 Years

rr_AverageAnnualReturnYear05

Lifetime

rr_AverageAnnualReturnSinceInception

5.91%

(Delaware Core Bond Fund) | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Management fees

rr_ManagementFeesOverAssets

0.50%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.54%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.04%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.39%)

^[3]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

0.65%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

66

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

292

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

536

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,236

Label

rr_AverageAnnualReturnLabel

(lifetime: 9/30/09-12/31/11)

1 Year

rr_AverageAnnualReturnYear01

8.31%

5 Years

rr_AverageAnnualReturnYear05

Lifetime

rr_AverageAnnualReturnSinceInception

7.23%

(Delaware Core Bond Fund) | Class R

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Management fees

rr_ManagementFeesOverAssets

0.50%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.60%

Other expenses

rr_OtherExpensesOverAssets

0.54%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.64%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.49%)

^[3]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

1.15%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

117

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

469

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

846

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,903

Label

rr_AverageAnnualReturnLabel

(lifetime: 9/30/09-12/31/11)

1 Year

rr_AverageAnnualReturnYear01

7.06%

5 Years

rr_AverageAnnualReturnYear05

Lifetime

rr_AverageAnnualReturnSinceInception

6.38%

(Delaware Corporate Bond Fund)

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

What is the Fund's investment objective?

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

Delaware Corporate Bond Fund seeks to provide investors with total return.

Expense [Heading]

rr_ExpenseHeading

What are the Fund's fees and expenses?

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 202% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

202.00%

Expense Breakpoint Discounts [Text]

rr_ExpenseBreakpointDiscounts

You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

100,000

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and reflects the applicable waivers and reimbursements for the 1-year contractual period and the total operating expenses without waivers for years 2 through 10. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

What are the Fund's principal investment strategies?

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund invests primarily in corporate bonds. Our focus is on corporate bonds that have investment grade credit ratings from a nationally recognized statistical rating organization (NRSRO). The bonds we select for the portfolio are typically rated BBB- and above by Standard & Poor's (S&P), Baa3 and above by Moody's Investors Service, Inc. (Moody's), or similarly rated by another NRSRO. We may also invest in unrated bonds, if we believe their credit quality is comparable to those that have investment grade ratings.

The Fund may also invest up to 20% of its net assets in high yield corporate bonds ("junk bonds"). In addition, the Fund may invest up to 35% of its total assets in foreign securities, but the Fund's total non-U.S.-dollar currency exposure will be limited, in the aggregate, to no more than 25% of net assets.

The average portfolio duration of the Fund will generally vary within two years (plus or minus) of the current average duration of the Barclays U.S. Corporate Investment Grade Index, which as of October 31, 2012, was 7.25 years. Duration measures a bond's sensitivity to interest rates by indicating the approximate change in a bond or bond fund's price given a 1% change in interest rates.

Under normal circumstances, the Fund will invest at least 80% of its net assets in corporate bonds. This policy is not a fundamental investment policy and can be changed without shareholder approval. However, shareholders will be given notice at least 60 days prior to any such change.

Risk [Heading]

rr_RiskHeading

What are the principal risks of investing in the Fund?

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio. Principal risks include:

Investments not guaranteed by the Manager or its affiliates — Investments in the Fund are not and will not be deposits with or liabilities of Macquarie Bank Limited ABN 46 008 583 542 and its holding companies, including their subsidiaries or related companies (Macquarie Group), and are subject to investment risk, including possible delays in repayment and loss of income and capital invested. No Macquarie Group company guarantees or will guarantee the performance of the Fund, the repayment of capital from the Fund, or any particular rate of return.

Market risk — The risk that all or a majority of the securities in a certain market — such as the stock or bond market — will decline in value because of factors such as adverse political or economic conditions, future expectations, investor confidence, or heavy institutional selling.

Interest rate risk — The risk that securities will decrease in value if interest rates rise. This risk is generally associated with bonds.

Credit risk — The risk that an issuer of a debt security, including a governmental issuer, may be unable to make interest payments and repay principal in a timely manner.

High yield (junk bond) risk — The risk that high yield securities, commonly known as "junk bonds," are subject to reduced creditworthiness of issuers; increased risk of default and a more limited and less liquid secondary market; and greater price volatility and risk of loss of income and principal than are higher rated securities. High yield bonds are sometimes issued by municipalities with less financial strength and therefore less ability to make projected debt payments on the bonds.

Bank loans and other indebtedness risk — The risk that the portfolio will not receive payment of principal, interest, and other amounts due in connection with these investments and will depend primarily on the financial condition of the borrower and the lending institution.

Foreign risk — The risk that foreign securities (particularly in emerging markets) may be adversely affected by political instability; changes in currency exchange rates; inefficient markets and higher transaction costs; foreign economic conditions; or inadequate or different regulatory and accounting standards.

Forward foreign currency risk — The use of forward foreign currency exchange contracts may substantially change a fund's exposure to currency exchange rates and could result in losses to the fund if currencies do not perform as the Manager expects. The use of these investments as a hedging technique to reduce a fund's exposure to currency risks may also reduce its ability to benefit from favorable changes in currency exchange rates.

Liquidity risk — The possibility that securities cannot be readily sold within seven days at approximately the price at which a fund has valued them.

Derivatives risk — Derivative contracts, such as options, futures, and swaps, may involve additional expenses (such as the payment of premiums) and are subject to significant loss if a security, or a securities index to which a derivative contract is associated, moves in the opposite direction from what the portfolio manager anticipated. Derivative contracts are also subject to the risk that the counterparty may fail to perform its obligations under the contract due to financial difficulties (such as a bankruptcy or reorganization).

Government and regulatory risk — The risk that governments or regulatory authorities have, from time to time, taken or considered actions that could adversely affect various sectors of the securities markets.

Risk Lose Money [Text]

rr_RiskLoseMoney

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

How has Delaware Corporate Bond Fund performed?

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for the 1-, 5-, and 10-year or lifetime periods compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future. The returns reflect expense caps in effect during certain of these periods. The returns would be lower without the expense caps. You may obtain the Fund's most recently available month-end performance by calling 800 523-1918 or by visiting our website at delawareinvestments.com/performance.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800 523-1918

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

delawareinvestments.com/performance

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

Year-by-year total return (Class A)*

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

As of September 30, 2012, Delaware Corporate Bond Fund's Class A shares had a calendar year-to-date return of 12.02%. During the periods illustrated in this bar chart, Class A's highest quarterly return was 14.62% for the quarter ended June 30, 2009 and its lowest quarterly return was -6.83% for the quarter ended September 30, 2008. The maximum Class A sales charge of 4.50%, which is normally deducted when you purchase shares, is not reflected in the highest/lowest quarterly returns or in the bar chart. If this sales charge were included, the returns would be less than those shown. The average annual returns in the table below do include the sales charge.

Performance Table Heading

rr_PerformanceTableHeading

Average annual total returns for periods ended December 31, 2011*

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is presented only for Class A shares of the Fund.

Performance Table Footnotes

rr_PerformanceTableFootnotesTextBlock

* Because the Fund has combined its retail and institutional prospectuses, the bar chart and the after tax returns in the average annual total returns table show the performance of the Fund's Class A shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

After-tax performance is presented only for Class A shares of the Fund. The after-tax returns for other Fund classes may vary. Actual after-tax returns depend on the investor's individual tax situation and may differ from the returns shown. After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs). The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

(Delaware Corporate Bond Fund) | Barclays U.S. Corporate Investment Grade Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

8.15%

5 Years

rr_AverageAnnualReturnYear05

6.82%

10 years or lifetime

rr_AverageAnnualReturnYear10

6.36%

(Delaware Corporate Bond Fund) | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

4.50%

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Management fees

rr_ManagementFeesOverAssets

0.48%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.30%

Other expenses

rr_OtherExpensesOverAssets

0.23%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.01%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.07%)

^[4]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

0.94%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

542

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

750

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

976

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,625

Annual Return 2002

rr_AnnualReturn2002

10.84%

Annual Return 2003

rr_AnnualReturn2003

12.71%

Annual Return 2004

rr_AnnualReturn2004

7.07%

Annual Return 2005

rr_AnnualReturn2005

1.85%

Annual Return 2006

rr_AnnualReturn2006

6.60%

Annual Return 2007

rr_AnnualReturn2007

3.10%

Annual Return 2008

rr_AnnualReturn2008

(8.44%)

Annual Return 2009

rr_AnnualReturn2009

28.84%

Annual Return 2010

rr_AnnualReturn2010

11.49%

Annual Return 2011

rr_AnnualReturn2011

7.31%

Year to Date Return, Label

rr_YearToDateReturnLabel

As of September 30, 2012, Delaware Corporate Bond Fund's Class A shares had a calendar year-to-date return of 12.02%

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Sep. 30, 2012

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

12.02%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

highest quarterly return was 14.62% for the quarter ended June 30, 2009

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

14.62%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

lowest quarterly return was -6.83% for the quarter ended September 30, 2008

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(6.83%)

1 Year

rr_AverageAnnualReturnYear01

2.41%

5 Years

rr_AverageAnnualReturnYear05

6.79%

10 years or lifetime

rr_AverageAnnualReturnYear10

7.27%

(Delaware Corporate Bond Fund) | Class A | return after taxes on distributions

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

0.03%

5 Years

rr_AverageAnnualReturnYear05

4.32%

10 years or lifetime

rr_AverageAnnualReturnYear10

4.88%

(Delaware Corporate Bond Fund) | Class A | return after taxes on distributions and sale of Fund shares

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

1.75%

5 Years

rr_AverageAnnualReturnYear05

4.35%

10 years or lifetime

rr_AverageAnnualReturnYear10

4.82%

(Delaware Corporate Bond Fund) | Class B

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

4.00%

^[2]

Management fees

rr_ManagementFeesOverAssets

0.48%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.23%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.71%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.02%)

^[4]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

1.69%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

572

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

762

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,076

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,832

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

172

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

537

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

926

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

1,832

1 Year

rr_AverageAnnualReturnYear01

2.70%

5 Years

rr_AverageAnnualReturnYear05

6.80%

10 years or lifetime

rr_AverageAnnualReturnYear10

7.12%

(Delaware Corporate Bond Fund) | Class C

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

1.00%

^[2]

Management fees

rr_ManagementFeesOverAssets

0.48%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.23%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.71%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.02%)

^[4]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

1.69%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

272

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

537

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

926

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,018

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

172

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

537

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

926

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

2,018

1 Year

rr_AverageAnnualReturnYear01

5.51%

5 Years

rr_AverageAnnualReturnYear05

6.98%

10 years or lifetime

rr_AverageAnnualReturnYear10

6.97%

(Delaware Corporate Bond Fund) | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Management fees

rr_ManagementFeesOverAssets

0.48%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.23%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.71%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.02%)

^[4]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

0.69%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

70

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

225

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

393

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

881

1 Year

rr_AverageAnnualReturnYear01

7.57%

5 Years

rr_AverageAnnualReturnYear05

8.09%

10 years or lifetime

rr_AverageAnnualReturnYear10

8.04%

(Delaware Corporate Bond Fund) | Class R

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Management fees

rr_ManagementFeesOverAssets

0.48%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.60%

Other expenses

rr_OtherExpensesOverAssets

0.23%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.31%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

1.19%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

121

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

403

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

707

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,569

Label

rr_AverageAnnualReturnLabel

(lifetime: 6/2/03-12/31/11)

1 Year

rr_AverageAnnualReturnYear01

7.04%

5 Years

rr_AverageAnnualReturnYear05

7.52%

Lifetime

rr_AverageAnnualReturnSinceInception

6.33%

(Delaware Extended Duration Bond Fund)

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

What is the Fund's investment objective?

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

Delaware Extended Duration Bond Fund seeks to provide investors with total return.

Expense [Heading]

rr_ExpenseHeading

What are the Fund's fees and expenses?

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 172% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

172.00%

Expense Breakpoint Discounts [Text]

rr_ExpenseBreakpointDiscounts

You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

100,000

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and reflects the applicable waivers and reimbursements for the 1-year contractual period and the total operating expenses without waivers for years 2 through 10. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

What are the Fund's principal investment strategies?

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund invests primarily in corporate bonds. Our focus is on corporate bonds that have investment grade credit ratings from a nationally recognized statistical rating organization (NRSRO). The bonds we select for the portfolio are typically rated BBB- and above by Standard & Poor's (S&P), Baa3 and above by Moody's Investors Service, Inc. (Moody's), or similarly rated by another NRSRO. We may also invest in unrated bonds, if we believe their credit quality is comparable to those that have investment grade ratings.

The Fund may also invest up to 20% of its net assets in high yield corporate bonds ("junk bonds"). In addition, the Fund may invest up to 35% of its total assets in foreign securities, but the Fund's total non-U.S.-dollar currency exposure will be limited, in the aggregate, to no more than 25% of net assets.

The average portfolio duration of the Fund will generally vary within two years (plus or minus) of the current average duration of the Barclays Long U.S. Corporate Index, which as of October 31, 2012, was 14 years. Duration measures a bond's sensitivity to interest rates by indicating the approximate change in a bond or bond fund's price given a 1% change in interest rates.

Under normal circumstances, the Fund will invest at least 80% of its net assets in corporate bonds. This policy is not a fundamental investment policy and can be changed without shareholder approval. However, shareholders will be given notice at least 60 days prior to any such change.

Risk [Heading]

rr_RiskHeading

What are the principal risks of investing in the Fund?

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio. Principal risks include:

Investments not guaranteed by the Manager or its affiliates — Investments in the Fund are not and will not be deposits with or liabilities of Macquarie Bank Limited ABN 46 008 583 542 and its holding companies, including their subsidiaries or related companies (Macquarie Group), and are subject to investment risk, including possible delays in repayment and loss of income and capital invested. No Macquarie Group company guarantees or will guarantee the performance of the Fund, the repayment of capital from the Fund, or any particular rate of return.

Market risk — The risk that all or a majority of the securities in a certain market — such as the stock or bond market — will decline in value because of factors such as adverse political or economic conditions, future expectations, investor confidence, or heavy institutional selling.

Interest rate risk — The risk that securities will decrease in value if interest rates rise. This risk is generally associated with bonds.

Credit risk — The risk that an issuer of a debt security, including a governmental issuer, may be unable to make interest payments and repay principal in a timely manner.

High yield (junk bond) risk — The risk that high yield securities, commonly known as "junk bonds," are subject to reduced creditworthiness of issuers; increased risk of default and a more limited and less liquid secondary market; and greater price volatility and risk of loss of income and principal than are higher rated securities. High yield bonds are sometimes issued by municipalities with less financial strength and therefore less ability to make projected debt payments on the bonds.

Bank loans and other indebtedness risk — The risk that the portfolio will not receive payment of principal, interest, and other amounts due in connection with these investments and will depend primarily on the financial condition of the borrower and the lending institution.

Foreign risk — The risk that foreign securities (particularly in emerging markets) may be adversely affected by political instability; changes in currency exchange rates; inefficient markets and higher transaction costs; foreign economic conditions; or inadequate or different regulatory and accounting standards.

Forward foreign currency risk — The use of forward foreign currency exchange contracts may substantially change a fund's exposure to currency exchange rates and could result in losses to the fund if currencies do not perform as the Manager expects. The use of these investments as a hedging technique to reduce a fund's exposure to currency risks may also reduce its ability to benefit from favorable changes in currency exchange rates.

Liquidity risk — The possibility that securities cannot be readily sold within seven days at approximately the price at which a fund has valued them.

Derivatives risk — Derivative contracts, such as options, futures, and swaps, may involve additional expenses (such as the payment of premiums) and are subject to significant loss if a security, or a securities index to which a derivative contract is associated, moves in the opposite direction from what the portfolio manager anticipated. Derivative contracts are also subject to the risk that the counterparty may fail to perform its obligations under the contract due to financial difficulties (such as a bankruptcy or reorganization).

Government and regulatory risk — The risk that governments or regulatory authorities have, from time to time, taken or considered actions that could adversely affect various sectors of the securities markets.

Risk Lose Money [Text]

rr_RiskLoseMoney

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

How has Delaware Extended Duration Bond Fund performed?

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for the 1-, 5-, and 10-year or lifetime periods compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future. The returns reflect expense caps in effect during certain of these periods. The returns would be lower without the expense caps. You may obtain the Fund's most recently available month-end performance by calling 800 523-1918 or by visiting our website at delawareinvestments.com/performance.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800 523-1918

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

delawareinvestments.com/performance

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

Year-by-year total return (Class A)*

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

As of September 30, 2012, the Fund's Class A shares had a calendar year-to-date return of 13.80%. During the periods illustrated in this bar chart, Class A's highest quarterly return was 14.88% for the quarter ended June 30, 2009 and its lowest quarterly return was -8.61% for the quarter ended September 30, 2008. The maximum Class A sales charge of 4.50%, which is normally deducted when you purchase shares, is not reflected in the highest/lowest quarterly returns or in the bar chart. If this fee were included, the returns would be less than those shown. The average annual returns in the table below do include the sales charge.

Performance Table Heading

rr_PerformanceTableHeading

Average annual total returns for periods ended December 31, 2011*

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is presented only for Class A shares of the Fund.

Performance Table Footnotes

rr_PerformanceTableFootnotesTextBlock

* Because the Fund has combined its retail and institutional prospectuses, the bar chart and the after tax returns in the average annual total returns table show the performance of the Fund's Class A shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

After-tax performance is presented only for Class A shares of the Fund. The after-tax returns for other Fund classes may vary. Actual after-tax returns depend on the investor's individual tax situation and may differ from the returns shown. After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs). The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

(Delaware Extended Duration Bond Fund) | Barclays Long U.S. Corporate Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

15.91%

5 Years

rr_AverageAnnualReturnYear05

8.51%

10 years or lifetime

rr_AverageAnnualReturnYear10

7.98%

(Delaware Extended Duration Bond Fund) | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

4.50%

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Management fees

rr_ManagementFeesOverAssets

0.54%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.30%

Other expenses

rr_OtherExpensesOverAssets

0.22%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.06%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.11%)

^[5]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

0.95%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

543

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

762

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

998

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,676

Annual Return 2002

rr_AnnualReturn2002

13.02%

Annual Return 2003

rr_AnnualReturn2003

15.04%

Annual Return 2004

rr_AnnualReturn2004

10.03%

Annual Return 2005

rr_AnnualReturn2005

2.85%

Annual Return 2006

rr_AnnualReturn2006

5.33%

Annual Return 2007

rr_AnnualReturn2007

3.02%

Annual Return 2008

rr_AnnualReturn2008

2.85%

Annual Return 2009

rr_AnnualReturn2009

24.96%

Annual Return 2010

rr_AnnualReturn2010

14.31%

Annual Return 2011

rr_AnnualReturn2011

16.50%

Year to Date Return, Label

rr_YearToDateReturnLabel

As of September 30, 2012, the Fund's Class A shares had a calendar year-to-date return of 13.80%

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Sep. 30, 2012

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

13.80%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

highest quarterly return was 14.88% for the quarter ended June 30, 2009

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

14.88%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

lowest quarterly return was -8.61% for the quarter ended September 30, 2008

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(8.61%)

1 Year

rr_AverageAnnualReturnYear01

11.22%

5 Years

rr_AverageAnnualReturnYear05

9.72%

10 years or lifetime

rr_AverageAnnualReturnYear10

9.44%

(Delaware Extended Duration Bond Fund) | Class A | return after taxes on distributions

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

8.14%

5 Years

rr_AverageAnnualReturnYear05

7.04%

10 years or lifetime

rr_AverageAnnualReturnYear10

6.81%

(Delaware Extended Duration Bond Fund) | Class A | return after taxes on distributions and sale of Fund shares

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

7.60%

5 Years

rr_AverageAnnualReturnYear05

6.76%

10 years or lifetime

rr_AverageAnnualReturnYear10

6.59%

(Delaware Extended Duration Bond Fund) | Class B

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

4.00%

^[2]

Management fees

rr_ManagementFeesOverAssets

0.54%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.22%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.76%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.06%)

^[5]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

1.70%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

573

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

773

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,099

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,883

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

173

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

548

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

949

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

1,883

1 Year

rr_AverageAnnualReturnYear01

11.66%

5 Years

rr_AverageAnnualReturnYear05

9.68%

10 years or lifetime

rr_AverageAnnualReturnYear10

9.27%

(Delaware Extended Duration Bond Fund) | Class C

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

1.00%

^[2]

Management fees

rr_ManagementFeesOverAssets

0.54%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.22%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.76%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.06%)

^[5]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

1.70%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

273

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

548

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

949

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,068

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

173

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

548

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

949

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

2,068

1 Year

rr_AverageAnnualReturnYear01

14.64%

5 Years

rr_AverageAnnualReturnYear05

9.92%

10 years or lifetime

rr_AverageAnnualReturnYear10

9.13%

(Delaware Extended Duration Bond Fund) | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Management fees

rr_ManagementFeesOverAssets

0.54%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.22%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.76%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.06%)

^[5]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

0.70%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

72

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

237

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

416

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

937

1 Year

rr_AverageAnnualReturnYear01

16.81%

5 Years

rr_AverageAnnualReturnYear05

10.99%

10 years or lifetime

rr_AverageAnnualReturnYear10

10.21%

(Delaware Extended Duration Bond Fund) | Class R

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Management fees

rr_ManagementFeesOverAssets

0.54%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.60%

Other expenses

rr_OtherExpensesOverAssets

0.22%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.36%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.16%)

^[5]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

1.20%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

122

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

415

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

729

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,621

Label

rr_AverageAnnualReturnLabel

(lifetime: 10/3/05-12/31/11)

1 Year

rr_AverageAnnualReturnYear01

16.20%

5 Years

rr_AverageAnnualReturnYear05

10.45%

Lifetime

rr_AverageAnnualReturnSinceInception

9.15%

(Delaware High-Yield Opportunities Fund)

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

What are the Fund's investment objectives?

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

Delaware High-Yield Opportunities Fund seeks total return and, as a secondary objective, high current income.

Expense [Heading]

rr_ExpenseHeading

What are the Fund's fees and expenses?

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 61% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

61.00%

Expense Breakpoint Discounts [Text]

rr_ExpenseBreakpointDiscounts

You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

100,000

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and reflects the applicable waivers and reimbursements for the 1-year contractual period and the total operating expenses without waivers for years 2 through 10. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

What are the Fund's principal investment strategies?

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund will invest primarily in corporate bonds rated BBB- or lower by Standard & Poor's (S&P), Baa3 or lower by Moody's Investors Services, Inc. (Moody's), or similarly rated by another nationally recognized statistical rating organization (NRSRO). These are commonly known as high yield bonds or junk bonds and involve greater risks than investment grade bonds. The Fund will also invest in unrated bonds we judge to be of comparable quality. Unrated bonds may be more speculative in nature than rated bonds. The Fund may also invest in U.S. and foreign government securities and corporate bonds of foreign issuers. The Fund may invest up to 25% of its total assets in foreign securities. In selecting bonds for the portfolio, we evaluate the income provided by the bond and the bond's appreciation potential as well as the issuer's ability to make income and principal payments.

Under normal circumstances, the Fund will invest at least 80% of its net assets in fixed income securities rated at the time of purchase BBB- or lower by S&P, Baa3 or lower by Moody's, or similarly rated by another NRSRO or, if unrated, judged to be of comparable quality. This policy is not a fundamental investment policy and can be changed without shareholder approval. However, shareholders will be given notice at least 60 days prior to any such change.

Risk [Heading]

rr_RiskHeading

What are the principal risks of investing in the Fund?

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio. Principal risks include:

Investments not guaranteed by the Manager or its affiliates — Investments in the Fund are not and will not be deposits with or liabilities of Macquarie Bank Limited ABN 46 008 583 542 and its holding companies, including their subsidiaries or related companies (Macquarie Group), and are subject to investment risk, including possible delays in repayment and loss of income and capital invested. No Macquarie Group company guarantees or will guarantee the performance of the Fund, the repayment of capital from the Fund, or any particular rate of return.

Market risk — The risk that all or a majority of the securities in a certain market — such as the stock or bond market — will decline in value because of factors such as adverse political or economic conditions, future expectations, investor confidence, or heavy institutional selling.

High yield (junk bond) risk — The risk that high yield securities, commonly known as "junk bonds," are subject to reduced creditworthiness of issuers; increased risk of default and a more limited and less liquid secondary market; and greater price volatility and risk of loss of income and principal than are higher rated securities. High yield bonds are sometimes issued by municipalities with less financial strength and therefore less ability to make projected debt payments on the bonds.

Interest rate risk — The risk that securities will decrease in value if interest rates rise. This risk is generally associated with bonds.

Credit risk — The risk that an issuer of a debt security, including a governmental issuer, may be unable to make interest payments and repay principal in a timely manner.

Derivatives risk — Derivative contracts, such as options, futures and swaps, may involve additional expenses (such as the payment of premiums) and are subject to significant loss if a security, or a securities index to which a derivative contract is associated, moves in the opposite direction from what the portfolio manager anticipated.

Foreign risk — The risk that foreign securities (particularly in emerging markets) may be adversely affected by political instability; changes in currency exchange rates; inefficient markets and higher transaction costs; foreign economic conditions; or inadequate or different regulatory and accounting standards.

Bank loans and other indebtedness risk — The risk that the portfolio will not receive payment of principal, interest, and other amounts due in connection with these investments and will depend primarily on the financial condition of the borrower and the lending institution.

Liquidity risk — The possibility that securities cannot be readily sold within seven days at approximately the price at which a fund has valued them.

Valuation risk — The risk that a less liquid secondary market may make it more difficult for a fund to obtain precise valuations of certain securities in its portfolio.

Redemption risk — If investors redeem more shares of a fund than are purchased for an extended period of time, a fund may be required to sell securities without regard to the investment merits of such actions. This could decrease a fund's asset base, potentially resulting in a higher expense ratio.

Counterparty risk — The risk that a counterparty to a derivative contract (such as a swap, futures, or options contract) or a repurchase agreement may fail to perform its obligations under the contract or agreement due to financial difficulties (such as a bankruptcy or reorganization).

Government and regulatory risk — The risk that governments or regulatory authorities have, from time to time, taken or considered actions that could adversely affect various sectors of the securities markets.

Risk Lose Money [Text]

rr_RiskLoseMoney

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

How has Delaware High-Yield Opportunities Fund performed?

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for the 1-, 5-, and 10-year or lifetime periods compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future. The returns reflect expense caps in effect during certain of these periods. The returns would be lower without the expense caps. You may obtain the Fund's most recently available month-end performance by calling 800 523-1918 or by visiting our website at delawareinvestments.com/performance.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800 523-1918

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

delawareinvestments.com/performance

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

Year-by-year total return (Class A)*

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

As of September 30, 2012, the Fund's Class A shares had a calendar year-to-date return of 13.52%. During the periods illustrated in this bar chart, Class A's highest quarterly return was 19.45% for the quarter ended June 30, 2009 and its lowest quarterly return was -18.08% for the quarter ended December 31, 2008. The maximum Class A sales charge of 4.50%, which is normally assessed when you purchase shares, is not reflected in the highest/lowest quarterly returns or in the bar chart. If this fee were included, the returns would be less than those shown. The average annual returns in the table below do include the sales charge.

Performance Table Heading

rr_PerformanceTableHeading

Average annual total returns for periods ended December 31, 2011*

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is presented only for Class A shares of the Fund.

Performance Table Footnotes

rr_PerformanceTableFootnotesTextBlock

* Because the Fund has combined its retail and institutional prospectuses, the bar chart and the after tax returns in the average annual total returns table show the performance of the Fund's Class A shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

After-tax performance is presented only for Class A shares of the Fund. The after-tax returns for other Fund classes may vary. Actual after-tax returns depend on the investor's individual tax situation and may differ from the returns shown. After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs). The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

(Delaware High-Yield Opportunities Fund) | BofA Merrill Lynch U.S. High Yield Constrained Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

4.37%

5 Years

rr_AverageAnnualReturnYear05

7.55%

10 years or lifetime

rr_AverageAnnualReturnYear10

8.74%

(Delaware High-Yield Opportunities Fund) | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

4.50%

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Management fees

rr_ManagementFeesOverAssets

0.65%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.30%

Other expenses

rr_OtherExpensesOverAssets

0.23%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.18%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.07%)

^[6]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

1.11%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

558

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

801

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,063

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,811

Annual Return 2002

rr_AnnualReturn2002

1.79%

Annual Return 2003

rr_AnnualReturn2003

29.41%

Annual Return 2004

rr_AnnualReturn2004

14.12%

Annual Return 2005

rr_AnnualReturn2005

3.04%

Annual Return 2006

rr_AnnualReturn2006

12.36%

Annual Return 2007

rr_AnnualReturn2007

1.61%

Annual Return 2008

rr_AnnualReturn2008

(25.83%)

Annual Return 2009

rr_AnnualReturn2009

49.69%

Annual Return 2010

rr_AnnualReturn2010

16.31%

Annual Return 2011

rr_AnnualReturn2011

1.91%

Year to Date Return, Label

rr_YearToDateReturnLabel

As of September 30, 2012, the Fund's Class A shares had a calendar year-to-date return of 13.52%

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Sep. 30, 2012

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

13.52%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

highest quarterly return was 19.45% for the quarter ended June 30, 2009

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

19.45%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

lowest quarterly return was -18.08% for the quarter ended December 31, 2008

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(18.08%)

1 Year

rr_AverageAnnualReturnYear01

(2.79%)

5 Years

rr_AverageAnnualReturnYear05

5.00%

10 years or lifetime

rr_AverageAnnualReturnYear10

8.31%

(Delaware High-Yield Opportunities Fund) | Class A | return after taxes on distributions

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(5.42%)

5 Years

rr_AverageAnnualReturnYear05

2.00%

10 years or lifetime

rr_AverageAnnualReturnYear10

5.17%

(Delaware High-Yield Opportunities Fund) | Class A | return after taxes on distributions and sale of Fund shares

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(1.81%)

5 Years

rr_AverageAnnualReturnYear05

2.43%

10 years or lifetime

rr_AverageAnnualReturnYear10

5.21%

(Delaware High-Yield Opportunities Fund) | Class B

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

4.00%

^[2]

Management fees

rr_ManagementFeesOverAssets

0.65%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.23%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.88%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.07%)

^[6]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

1.81%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

584

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

809

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,160

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,013

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

184

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

584

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

1,010

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

2,013

1 Year

rr_AverageAnnualReturnYear01

(2.34%)

5 Years

rr_AverageAnnualReturnYear05

5.03%

10 years or lifetime

rr_AverageAnnualReturnYear10

8.18%

(Delaware High-Yield Opportunities Fund) | Class C

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

1.00%

^[2]

Management fees

rr_ManagementFeesOverAssets

0.65%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.23%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.88%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.07%)

^[6]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

1.81%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

284

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

584

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,010

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,195

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

184

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

584

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

1,010

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

2,195

1 Year

rr_AverageAnnualReturnYear01

0.25%

5 Years

rr_AverageAnnualReturnYear05

5.19%

10 years or lifetime

rr_AverageAnnualReturnYear10

8.03%

(Delaware High-Yield Opportunities Fund) | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Management fees

rr_ManagementFeesOverAssets

0.65%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.23%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.88%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.07%)

^[6]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

0.81%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

83

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

274

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

481

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,078

1 Year

rr_AverageAnnualReturnYear01

2.20%

5 Years

rr_AverageAnnualReturnYear05

6.29%

10 years or lifetime

rr_AverageAnnualReturnYear10

9.14%

(Delaware High-Yield Opportunities Fund) | Class R

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Management fees

rr_ManagementFeesOverAssets

0.65%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.60%

Other expenses

rr_OtherExpensesOverAssets

0.23%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.48%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.17%)

^[6]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

1.31%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

133

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

451

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

792

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,754

Label

rr_AverageAnnualReturnLabel

(lifetime: 6/2/03-12/31/11)

1 Year

rr_AverageAnnualReturnYear01

1.71%

5 Years

rr_AverageAnnualReturnYear05

5.76%

Lifetime

rr_AverageAnnualReturnSinceInception

7.98%

(Delaware Diversified Floating Rate Fund)

Risk/Return:

rr_RiskReturnAbstract

Objective [Heading]

rr_ObjectiveHeading

What is the Fund's investment objective?

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

Delaware Diversified Floating Rate Fund seeks total return.

Expense [Heading]

rr_ExpenseHeading

What are the Fund's fees and expenses?

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 97% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

97.00%

Expense Breakpoint Discounts [Text]

rr_ExpenseBreakpointDiscounts

You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

100,000

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and reflects the applicable waivers and reimbursements for the 1-year contractual period and the total operating expenses without waivers for years 2 through 10. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

What are the Fund's principal investment strategies?

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

Under normal circumstances, the Fund will invest at least 80% of its net assets in floating-rate securities, including but not limited to, investment grade corporate bonds, bank loans, high yield bonds, nonagency mortgage-backed securities, asset-backed securities, securities issued or guaranteed by the U.S. government, municipal bonds, securities of foreign issuers in both developed and emerging markets, and may include derivative instruments that attempt to achieve a floating rate of income for the Fund when they are combined with a group of fixed-rate securities (the 80% Policy). The Manager will determine how much of the Fund's assets to allocate among the different types of securities in which the Fund may invest based on our evaluation of economic and market conditions and our assessment of the returns and potential for appreciation that can be achieved from various sectors of the fixed income market.

The instruments listed in the preceding paragraph may be variable and floating-rate fixed income securities that generally pay interest at rates that adjust whenever a specified interest rate changes and/or reset on predetermined dates (such as the last day of a month or calendar quarter). Derivative instruments may be utilized to effectively convert the fixed-rate interest payments from a group of certain Fund portfolio securities into floating-rate interest payments. The Fund may also invest in securities other than those listed above. The average portfolio duration (that is, the sensitivity to general changes in interest rates) of this Fund will generally not exceed one year.

Up to 50% of the Fund's total assets may be allocated to below-investment-grade securities within the Fund. Investments in emerging markets will, in the aggregate, be limited to no more than 15% of the Fund's total assets. We will limit non-U.S.-dollar-denominated securities to no more than 50% of net assets, but total non-U.S.-dollar currency exposure will be limited, in the aggregate, to no more than 25% of net assets. The Fund may also invest up to 50% of its total assets in a wide range of derivative instruments, including options, futures contracts, options on futures contracts, and swaps. In addition, the Fund may hold a portion of its assets in cash or cash equivalents. The Fund's 80% Policy described above may be changed without shareholder approval. However, shareholders will be given at least 60 days' notice prior to any such change.

Risk [Heading]

rr_RiskHeading

What are the principal risks of investing in the Fund?

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio. Principal risks include:

Investments not guaranteed by the Manager or its affiliates — Investments in the Fund are not and will not be deposits with or liabilities of Macquarie Bank Limited ABN 46 008 583 542 and its holding companies, including their subsidiaries or related companies (Macquarie Group), and are subject to investment risk, including possible delays in repayment and loss of income and capital invested. No Macquarie Group company guarantees or will guarantee the performance of the Fund, the repayment of capital from the Fund, or any particular rate of return.

Market risk — The risk that all or a majority of the securities in a certain market — such as the stock or bond market — will decline in value because of factors such as adverse political or economic conditions, future expectations, investor confidence, or heavy institutional selling.

Credit risk — The risk that an issuer of a debt security, including a governmental issuer, may be unable to make interest payments and repay principal in a timely manner.

Bank loans and other indebtedness risk — The risk that the portfolio will not receive payment of principal, interest, and other amounts due in connection with these investments and will depend primarily on the financial condition of the borrower and the lending institution.

Interest rate risk — The risk that securities will decrease in value if interest rates rise. This risk is generally associated with bonds.

High yield (junk bond) risk — The risk that high yield securities, commonly known as "junk bonds," are subject to reduced creditworthiness of issuers; increased risk of default and a more limited and less liquid secondary market; and greater price volatility and risk of loss of income and principal than are higher rated securities.

Prepayment risk — The risk that the principal on a bond that is held by a portfolio will be prepaid prior to maturity at a time when interest rates are lower than what that bond was paying. A portfolio may then have to reinvest that money at a lower interest rate.

Foreign risk — The risk that foreign securities (particularly in emerging markets) may be adversely affected by political instability; changes in currency exchange rates; inefficient markets and higher transaction costs; foreign economic conditions; or inadequate or different regulatory and accounting standards.

Forward foreign currency risk — The use of forward foreign currency exchange contracts may substantially change a fund's exposure to currency exchange rates and could result in losses to the fund if currencies do not perform as the Manager expects. The use of these investments as a hedging technique to reduce a fund's exposure to currency risks may also reduce its ability to benefit from favorable changes in currency exchange rates.

Liquidity risk — The possibility that securities cannot be readily sold within seven days at approximately the price at which a fund has valued them.

Derivatives risk — Derivative contracts, such as options, futures, and swaps, may involve additional expenses (such as the payment of premiums) and are subject to significant loss if a security, or a securities index to which a derivative contract is associated, moves in the opposite direction from what the portfolio manager anticipated. Derivative contracts are also subject to the risk that the counterparty may fail to perform its obligations under the contract due to financial difficulties (such as a bankruptcy or reorganization).

Valuation risk — The risk that a less liquid secondary market may make it more difficult for a fund to obtain precise valuations of certain securities in its portfolio.

Government and regulatory risk — The risk that governments or regulatory authorities have, from time to time, taken or considered actions that could adversely affect various sectors of the securities markets.

Risk Lose Money [Text]

rr_RiskLoseMoney

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

How has Delaware Diversified Floating Rate Fund performed?

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for the 1-year and lifetime periods compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future. The returns reflect expense caps in effect during these periods. The returns would be lower without the expense caps. You may obtain the Fund's most recently available month-end performance by calling 800 523-1918 or by visiting our website at delawareinvestments.com/performance.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800 523-1918

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

delawareinvestments.com/performance

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

Year-by-year total return (Class A)*

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

As of September 30, 2012, the Fund's Class A shares had a calendar year-to-date return of 4.64%. During the periods illustrated in this bar chart, Class A's highest quarterly return was 1.68% for the quarter ended September 30, 2010 and its lowest quarterly return was -2.42% for the quarter ended September 30,2011. The maximum Class A sales charge of 2.75%, which is normally deducted when you purchase shares, is not reflected in the highest/lowest quarterly returns or in the bar chart. If this sales charge were included, the returns would be less than those shown. The average annual returns in the table below do include the sales charge.

Performance Table Heading

rr_PerformanceTableHeading

Average annual total returns for periods ended December 31, 2011*

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is presented only for Class A shares of the Fund.

Performance Table Footnotes

rr_PerformanceTableFootnotesTextBlock

* Because the Fund has combined its retail and institutional prospectuses, the bar chart and the after tax returns in the average annual total returns table show the performance of the Fund's Class A shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

After-tax performance is presented only for Class A shares of the Fund. The after-tax returns for other Fund classes may vary. Actual after-tax returns depend on the investor's individual tax situation and may differ from the returns shown. After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs). The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

(Delaware Diversified Floating Rate Fund) | BofA Merrill Lynch U.S. Dollar 3-Month LIBOR Constant Maturity Index (reflects no deduction for fees, expenses, or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

0.27%

Lifetime

rr_AverageAnnualReturnSinceInception

0.31%

^[8]

(Delaware Diversified Floating Rate Fund) | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

2.75%

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Management fees

rr_ManagementFeesOverAssets

0.50%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.30%

Other expenses

rr_OtherExpensesOverAssets

0.32%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.12%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.07%)

^[7]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

1.05%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

379

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

614

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

868

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,595

Annual Return 2011

rr_AnnualReturn2011

0.17%

Year to Date Return, Label

rr_YearToDateReturnLabel

As of September 30, 2012, the Fund's Class A shares had a calendar year-to-date return of 4.64%

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Sep. 30, 2012

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

4.64%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

highest quarterly return was 1.68% for the quarter ended September 30, 2010

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2010

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

1.68%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

lowest quarterly return was -2.42% for the quarter ended September 30,2011

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(2.42%)

1 Year

rr_AverageAnnualReturnYear01

(2.56%)

Lifetime

rr_AverageAnnualReturnSinceInception

0.07%

^[8]

(Delaware Diversified Floating Rate Fund) | Class A | return after taxes on distributions

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(3.26%)

Lifetime

rr_AverageAnnualReturnSinceInception

(0.68%)

^[8]

(Delaware Diversified Floating Rate Fund) | Class A | return after taxes on distributions and sale of Fund shares

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(1.67%)

Lifetime

rr_AverageAnnualReturnSinceInception

(0.37%)

^[8]

(Delaware Diversified Floating Rate Fund) | Class C

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

1.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

0.50%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.32%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.82%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.02%)

^[7]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

1.80%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

283

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

571

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

983

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,136

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

183

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

571

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

983

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

2,136

1 Year

rr_AverageAnnualReturnYear01

(1.54%)

Lifetime

rr_AverageAnnualReturnSinceInception

0.85%

^[8]

(Delaware Diversified Floating Rate Fund) | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Management fees

rr_ManagementFeesOverAssets

0.50%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.32%

Total annual fund operating expenses

rr_ExpensesOverAssets

0.82%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.02%)

^[7]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

0.80%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

82

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

260

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

453

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,012

1 Year

rr_AverageAnnualReturnYear01

0.44%

Lifetime

rr_AverageAnnualReturnSinceInception

1.86%

^[8]

(Delaware Diversified Floating Rate Fund) | Class R

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases as a percentage of offering price

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Management fees

rr_ManagementFeesOverAssets

0.50%

Distribution and service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.60%

Other expenses

rr_OtherExpensesOverAssets

0.32%

Total annual fund operating expenses

rr_ExpensesOverAssets

1.42%

Fee waivers and expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[7]

Total annual fund operating expenses after fee waivers and expense reimbursements

rr_NetExpensesOverAssets

1.30%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

132

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

438

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

765

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,692

1 Year

rr_AverageAnnualReturnYear01

(0.79%)

Lifetime

rr_AverageAnnualReturnSinceInception

1.33%

^[8]

[1] Class C shares redeemed within one year of purchase are subject to a 1.00% contingent deferred sales charge (CDSC).

[2] If you redeem Class B shares during the first year after you buy them, you will pay a contingent deferred sales charge (CDSC) of 4.00%, which declines to 3.00% during the second year, 2.25% during the third year, 1.50% during the fourth and fifth years, 1.00% during the sixth year, and 0% thereafter. Class C shares redeemed within one year of purchase are subject to a 1.00% CDSC.

[3] The Fund's investment manager, Delaware Management Company (Manager), has contractually agreed to waive all or a portion of its investment advisory fees and/or pay/reimburse expenses (excluding any 12b-1 plan, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) in order to prevent annual fund operating expenses from exceeding, in an aggregate amount, 0.65% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. In addition, the Fund's distributor, Delaware Distributors, L.P. (Distributor), has contracted to limit the Class A and Class R shares' 12b-1 fee for the Fund from November 28, 2012 through November 28, 2013 to no more than 0.25% and 0.50% of average daily net assets, respectively. These waivers and reimbursements may only be terminated by agreement of the Manager and the Fund.

[4] The Fund's investment manager, Delaware Management Company (Manager), is contractually waiving its investment advisory fees and/or paying expenses (excluding any 12b-1 fees, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) to the extent necessary to prevent total annual fund operating expenses from exceeding 0.69% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. The Fund's distributor, Delaware Distributors, L.P. (Distributor), has also contracted to limit the Class A and Class R shares' 12b-1 fees from November 28, 2012 through November 28, 2013 to no more than 0.25% and 0.50% of their respective average daily net assets. These waivers and reimbursements may only be terminated by agreement of the Manager and the Distributor, as applicable, and the Fund.

[5] The Fund's investment manager, Delaware Management Company (Manager), is contractually waiving its investment advisory fees and/or paying expenses (excluding any 12b-1 fees, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) to the extent necessary to prevent total annual fund operating expenses from exceeding 0.70% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. The Fund's distributor, Delaware Distributors, L.P. (Distributor), has also contracted to limit the Class A and Class R shares' 12b-1 fees from November 28, 2012 through November 28, 2013 to no more than 0.25% and 0.50% of their respective average daily net assets. These waivers and reimbursements may only be terminated by agreement of the Manager and the Distributor, as applicable, and the Fund.

[6] The Fund's investment manager, Delaware Management Company (Manager), is contractually waiving its investment advisory fees and/or paying expenses (excluding any 12b-1 plan, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) to the extent necessary to prevent total annual fund operating expenses from exceeding 0.81% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. The Fund's distributor, Delaware Distributors, L.P. (Distributor), has also contracted to limit the Class R shares' 12b-1 fees to no more than 0.50% of its average daily net assets from November 28, 2012 through November 28, 2013. These waivers and reimbursements may only be terminated by agreement of the Manager and the Distributor, as applicable, and the Fund. Additionally, the Fund's Class A shares are subject to a blended 12b-1 fee of 0.10% on all shares acquired prior to June 1, 1992 and 0.30% on all shares acquired on or after June 1, 1992. All Class A shares currently bear 12b-1 fees at the same rate, the blended rate based on the formula described above. This method of calculating Class A 12b-1 fees may be discontinued at the sole discretion of the Fund's Board.

[7] The Fund's investment manager, Delaware Management Company (Manager), has contractually agreed to waive all or a portion of its investment advisory fees and/or pay/reimburse expenses (excluding any 12b-1 plan, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) in order to prevent annual fund operating expenses from exceeding, in an aggregate amount, 0.80% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. In addition, the Fund's distributor, Delaware Distributors, L.P. (Distributor), has contracted to limit the Class A and Class R shares' 12b-1 fee for the Fund to no more than 0.25% and 0.50% of average daily net assets, respectively, from November 28, 2012 through November 28, 2013. These waivers and reimbursements may only be terminated by agreement of the Manager or Distributor, as applicable, and the Fund.

[8] Lifetime (2/26/10-12/31/11)

XML

(Delaware Diversified Floating Rate Fund)

What is the Fund's investment objective?

Delaware Diversified Floating Rate Fund seeks total return.

What are the Fund's fees and expenses?

The following table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales-charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Delaware Investments® Funds. More information about these and other discounts is available from your financial advisor, in the Fund's prospectus under the section entitled "About your account," and in the Fund's statement of additional information under the section entitled "Purchasing shares."

Shareholder fees (fees paid directly from your investment)

Shareholder Fees (Delaware Diversified Floating Rate Fund)	Class A	Class C		Class R	Institutional Class
Maximum sales charge (load) imposed on purchases as a percentage of offering price	2.75%	none		none	none
Maximum contingent deferred sales charge (load) as a percentage of original purchase price or redemption price, whichever is lower	none	1.00%	[1]	none	none

Annual fund operating expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses (Delaware Diversified Floating Rate Fund)		Class A	Class C	Class R	Institutional Class
Management fees		0.50%	0.50%	0.50%	0.50%
Distribution and service (12b-1) fees		0.30%	1.00%	0.60%	none
Other expenses		0.32%	0.32%	0.32%	0.32%
Total annual fund operating expenses		1.12%	1.82%	1.42%	0.82%
Fee waivers and expense reimbursements	[1]	(0.07%)	(0.02%)	(0.12%)	(0.02%)
Total annual fund operating expenses after fee waivers and expense reimbursements		1.05%	1.80%	1.30%	0.80%

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and reflects the applicable waivers and reimbursements for the 1-year contractual period and the total operating expenses without waivers for years 2 through 10. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example (Delaware Diversified Floating Rate Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	379	614	868	1,595
Class C	283	571	983	2,136
Class R	132	438	765	1,692
Institutional Class	82	260	453	1,012

Expense Example, No Redemption (Delaware Diversified Floating Rate Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class C	183	571	983	2,136

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 97% of the average value of its portfolio.

What are the Fund's principal investment strategies?

Under normal circumstances, the Fund will invest at least 80% of its net assets in floating-rate securities, including but not limited to, investment grade corporate bonds, bank loans, high yield bonds, nonagency mortgage-backed securities, asset-backed securities, securities issued or guaranteed by the U.S. government, municipal bonds, securities of foreign issuers in both developed and emerging markets, and may include derivative instruments that attempt to achieve a floating rate of income for the Fund when they are combined with a group of fixed-rate securities (the 80% Policy). The Manager will determine how much of the Fund's assets to allocate among the different types of securities in which the Fund may invest based on our evaluation of economic and market conditions and our assessment of the returns and potential for appreciation that can be achieved from various sectors of the fixed income market.

The instruments listed in the preceding paragraph may be variable and floating-rate fixed income securities that generally pay interest at rates that adjust whenever a specified interest rate changes and/or reset on predetermined dates (such as the last day of a month or calendar quarter). Derivative instruments may be utilized to effectively convert the fixed-rate interest payments from a group of certain Fund portfolio securities into floating-rate interest payments. The Fund may also invest in securities other than those listed above. The average portfolio duration (that is, the sensitivity to general changes in interest rates) of this Fund will generally not exceed one year.

Up to 50% of the Fund's total assets may be allocated to below-investment-grade securities within the Fund. Investments in emerging markets will, in the aggregate, be limited to no more than 15% of the Fund's total assets. We will limit non-U.S.-dollar-denominated securities to no more than 50% of net assets, but total non-U.S.-dollar currency exposure will be limited, in the aggregate, to no more than 25% of net assets. The Fund may also invest up to 50% of its total assets in a wide range of derivative instruments, including options, futures contracts, options on futures contracts, and swaps. In addition, the Fund may hold a portion of its assets in cash or cash equivalents. The Fund's 80% Policy described above may be changed without shareholder approval. However, shareholders will be given at least 60 days' notice prior to any such change.

What are the principal risks of investing in the Fund?

Investing in any mutual fund involves the risk that you may lose part or all of the money you invest. Over time, the value of your investment in the Fund will increase and decrease according to changes in the value of the securities in the Fund's portfolio. Principal risks include:

Investments not guaranteed by the Manager or its affiliates — Investments in the Fund are not and will not be deposits with or liabilities of Macquarie Bank Limited ABN 46 008 583 542 and its holding companies, including their subsidiaries or related companies (Macquarie Group), and are subject to investment risk, including possible delays in repayment and loss of income and capital invested. No Macquarie Group company guarantees or will guarantee the performance of the Fund, the repayment of capital from the Fund, or any particular rate of return.

Market risk — The risk that all or a majority of the securities in a certain market — such as the stock or bond market — will decline in value because of factors such as adverse political or economic conditions, future expectations, investor confidence, or heavy institutional selling.

Credit risk — The risk that an issuer of a debt security, including a governmental issuer, may be unable to make interest payments and repay principal in a timely manner.

Bank loans and other indebtedness risk — The risk that the portfolio will not receive payment of principal, interest, and other amounts due in connection with these investments and will depend primarily on the financial condition of the borrower and the lending institution.

Interest rate risk — The risk that securities will decrease in value if interest rates rise. This risk is generally associated with bonds.

High yield (junk bond) risk — The risk that high yield securities, commonly known as "junk bonds," are subject to reduced creditworthiness of issuers; increased risk of default and a more limited and less liquid secondary market; and greater price volatility and risk of loss of income and principal than are higher rated securities.

Prepayment risk — The risk that the principal on a bond that is held by a portfolio will be prepaid prior to maturity at a time when interest rates are lower than what that bond was paying. A portfolio may then have to reinvest that money at a lower interest rate.

Foreign risk — The risk that foreign securities (particularly in emerging markets) may be adversely affected by political instability; changes in currency exchange rates; inefficient markets and higher transaction costs; foreign economic conditions; or inadequate or different regulatory and accounting standards.

Forward foreign currency risk — The use of forward foreign currency exchange contracts may substantially change a fund's exposure to currency exchange rates and could result in losses to the fund if currencies do not perform as the Manager expects. The use of these investments as a hedging technique to reduce a fund's exposure to currency risks may also reduce its ability to benefit from favorable changes in currency exchange rates.

Liquidity risk — The possibility that securities cannot be readily sold within seven days at approximately the price at which a fund has valued them.

Derivatives risk — Derivative contracts, such as options, futures, and swaps, may involve additional expenses (such as the payment of premiums) and are subject to significant loss if a security, or a securities index to which a derivative contract is associated, moves in the opposite direction from what the portfolio manager anticipated. Derivative contracts are also subject to the risk that the counterparty may fail to perform its obligations under the contract due to financial difficulties (such as a bankruptcy or reorganization).

Valuation risk — The risk that a less liquid secondary market may make it more difficult for a fund to obtain precise valuations of certain securities in its portfolio.

Government and regulatory risk — The risk that governments or regulatory authorities have, from time to time, taken or considered actions that could adversely affect various sectors of the securities markets.

How has Delaware Diversified Floating Rate Fund performed?

The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund's performance from year to year and by showing how the Fund's average annual returns for the 1-year and lifetime periods compare with those of a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how it will perform in the future. The returns reflect expense caps in effect during these periods. The returns would be lower without the expense caps. You may obtain the Fund's most recently available month-end performance by calling 800 523-1918 or by visiting our website at delawareinvestments.com/performance.

Year-by-year total return (Class A)*

As of September 30, 2012, the Fund's Class A shares had a calendar year-to-date return of 4.64%. During the periods illustrated in this bar chart, Class A's highest quarterly return was 1.68% for the quarter ended September 30, 2010 and its lowest quarterly return was -2.42% for the quarter ended September 30,2011. The maximum Class A sales charge of 2.75%, which is normally deducted when you purchase shares, is not reflected in the highest/lowest quarterly returns or in the bar chart. If this sales charge were included, the returns would be less than those shown. The average annual returns in the table below do include the sales charge.

Average annual total returns for periods ended December 31, 2011*

Average Annual Total Returns (Delaware Diversified Floating Rate Fund)	1 Year	Lifetime
Class A	(2.56%)	0.07%	[1]
Class A return after taxes on distributions	(3.26%)	(0.68%)	[1]
Class A return after taxes on distributions and sale of Fund shares	(1.67%)	(0.37%)	[1]
Class C	(1.54%)	0.85%	[1]
Class R	(0.79%)	1.33%	[1]
Institutional Class	0.44%	1.86%	[1]
BofA Merrill Lynch U.S. Dollar 3-Month LIBOR Constant Maturity Index (reflects no deduction for fees, expenses, or taxes)	0.27%	0.31%	[1]

* Because the Fund has combined its retail and institutional prospectuses, the bar chart and the after tax returns in the average annual total returns table show the performance of the Fund's Class A shares.

After-tax performance is presented only for Class A shares of the Fund. The after-tax returns for other Fund classes may vary. Actual after-tax returns depend on the investor's individual tax situation and may differ from the returns shown. After-tax returns are not relevant for shares held in tax-deferred investment vehicles such as employer-sponsored 401(k) plans and individual retirement accounts (IRAs). The after-tax returns shown are calculated using the highest individual federal marginal income tax rates in effect during the periods presented and do not reflect the impact of state and local taxes.

[1] Class C shares redeemed within one year of purchase are subject to a 1.00% contingent deferred sales charge (CDSC).

[1] The Fund's investment manager, Delaware Management Company (Manager), has contractually agreed to waive all or a portion of its investment advisory fees and/or pay/reimburse expenses (excluding any 12b-1 plan, taxes, interest, inverse floater program expenses, short sale and dividend interest expenses, brokerage fees, certain insurance costs, and nonroutine expenses or costs, including, but not limited to, those relating to reorganizations, litigation, conducting shareholder meetings, and liquidations) in order to prevent annual fund operating expenses from exceeding, in an aggregate amount, 0.80% of the Fund's average daily net assets from November 28, 2012 through November 28, 2013. In addition, the Fund's distributor, Delaware Distributors, L.P. (Distributor), has contracted to limit the Class A and Class R shares' 12b-1 fee for the Fund to no more than 0.25% and 0.50% of average daily net assets, respectively, from November 28, 2012 through November 28, 2013. These waivers and reimbursements may only be terminated by agreement of the Manager or Distributor, as applicable, and the Fund.

[1] Lifetime (2/26/10-12/31/11)