485BPOS

Registration No. 333-147208

File No. 811-22142

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC  20549

FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933	x
Pre-Effective Amendment No.__	o
Post-Effective Amendment No. 6	x
and/or
REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940	x
Amendment No. 8	x

OPPENHEIMER ROCHESTER^® INTERMEDIATE TERM MUNICIPAL FUND*

(Exact Name of Registrant as Specified in Charter)

6803 South Tucson Way, Centennial, Colorado 80112-3924

(Address of Principal Executive Offices)                 (Zip Code)

(303) 768-3200

(Registrant’s Telephone Number, including Area Code)

Arthur S. Gabinet, Esq.

OFI Global Asset Management, Inc.

Two World Financial Center, 225 Liberty Street New York, New York 10281-1008

(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)

o on _______________ pursuant to paragraph (b)

o 60 days after filing pursuant to paragraph (a)(1)

o on _______________ pursuant to paragraph (a)(1)

o 75 days after filing pursuant to paragraph (a)(2)

o on _______________ pursuant to paragraph (a)(2) of Rule 485.

If appropriate, check the following box:

o 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 the requirements for effectiveness of this Registration Statement pursuant to 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 New York and State of New York the 11th day of February, 2013.

Oppenheimer Rochester Intermediate Term Municipal Fund
By:	William F. Glavin, Jr.*
	William F. Glavin, Jr.*, President, Principal Executive Officer and Trustee

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

Signatures	Title	Date
Brian F. Wruble*	Chairman of the
Brian F. Wruble	Board of Trustees	February 11, 2013
William F. Glavin, Jr.*	President, Principal
William F. Glavin, Jr.	Executive Officer and Trustee	February 11, 2013
Brian W. Wixted*	Treasurer, Principal	February 11, 2013
Brian W. Wixted	Financial & Accounting Officer
David K. Downes*	Trustee	February 11, 2013
David K. Downes
Matthew P. Fink*	Trustee	February 11, 2013
Matthew P. Fink
Phillip A. Griffiths*	Trustee	February 11, 2013
Phillip A. Griffiths
Mary F. Miller*	Trustee	February 11, 2013
Mary F. Miller
Joel W. Motley*	Trustee	February 11, 2013
Joel W. Motley
Mary Ann Tynan*	Trustee	February 11, 2013
Mary Ann Tynan
Joseph M. Wikler*	Trustee	February 11, 2013
Joseph M. Wikler
Peter I. Wold*	Trustee	February 11, 2013
Peter I. Wold

*By:	/s/ Mitchell J. Lindauer
	Mitchell J. Lindauer, Attorney-in-Fact

EXHIBIT INDEX

Exhibit No.	Description
Ex-101.INS	XBRL Instance Document
Ex-101.SCH	XBRL Taxonomy Extension Schema Document
Ex-101.CAL	XBRL Taxonomy Extension Calculation Linkbase Document
Ex-101.DEF	XBRL Taxonomy Extension Definition Linkbase
Ex-101.LAB	XBRL Taxonomy Extension Labels Linkbase
Ex-101.PRE	XBRL Taxonomy Extension Presentation Linkbase Document

XML

Expense Example, No Redemption (dei_DocumentInformationDocumentAxis, (Oppenheimer Rochester® Intermediate Term Municipal Fund), USD $)	0 Months Ended
	Jan. 28, 2013
Class A
Expense Example, No Redemption:
Expense Example, No Redemption, 1 Year	$ 323
Expense Example, No Redemption, 3 Years	572
Expense Example, No Redemption, 5 Years	840
Expense Example, No Redemption, 10 Years	1,605
Class C
Expense Example, No Redemption:
Expense Example, No Redemption, 1 Year	180
Expense Example, No Redemption, 3 Years	638
Expense Example, No Redemption, 5 Years	1,122
Expense Example, No Redemption, 10 Years	1,978
Class Y
Expense Example, No Redemption:
Expense Example, No Redemption, 1 Year	78
Expense Example, No Redemption, 3 Years	300
Expense Example, No Redemption, 5 Years	541
Expense Example, No Redemption, 10 Years	$ 1,230

XML

(Oppenheimer Rochester® Intermediate Term Municipal Fund)

Investment Objective. The Fund seeks current interest income exempt from federal individual income tax.

Fees and Expenses of the Fund. This table describes the fees and expenses that you may pay if you buy and hold or redeem shares of the Fund. You may qualify for sales charge discounts if you (or you and your spouse) invest, or agree to invest in the future, at least $100,000 in certain funds in the Oppenheimer family of funds. More information about these and other discounts is available from your financial professional and in the section "About Your Account" beginning on page 11 of the prospectus and in the sections "How to Buy Shares" beginning on page 53 and "Appendix A" in the Fund's Statement of Additional Information.

Shareholder Fees(fees paid directly from your investment)

Shareholder Fees (Oppenheimer Rochester® Intermediate Term Municipal Fund)	Class A	Class C	Class Y
Maximum Sales Charge (Load) imposed on purchases (as % of offering price)	2.25%	none	none
Maximum Deferred Sales Charge (Load) (as % of the lower of the original offering price or redemption proceeds)	none	1.00%	none

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses (Oppenheimer Rochester® Intermediate Term Municipal Fund)		Class A	Class C	Class Y
Management Fees		0.60%	0.60%	0.60%
Distribution and/or Service (12b-1) Fees		0.19%	0.99%	none
Total Other Expenses		0.38%	0.54%	0.42%
Interest and Fees from Borrowing		0.03%	0.03%	0.03%
Other Expenses		0.35%	0.51%	0.39%
Total Annual Fund Operating Expenses		1.17%	2.13%	1.02%
Fee Waiver and/or Expense Reimbursement	[1]	(0.19%)	(0.37%)	(0.26%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.98%	1.76%	0.76%

Example. The following 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 a class of shares of the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your expenses would be as follows:

If shares are redeemed

Expense Example (Oppenheimer Rochester® Intermediate Term Municipal Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	323	572	840	1,605
Class C	280	638	1,122	1,978
Class Y	78	300	541	1,230

If shares are not redeemed

Expense Example, No Redemption (Oppenheimer Rochester® Intermediate Term Municipal Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	323	572	840	1,605
Class C	180	638	1,122	1,978
Class Y	78	300	541	1,230

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 the 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 17% of the average value of its portfolio.

Principal Investment Strategies. Under normal market conditions the Fund invests at least 80% of its net assets, plus borrowings for investment purposes, in securities that pay interest that is, in the opinion of bond counsel to the issuer at the time the security is issued, exempt from federal individual income tax. Securities that generate income subject to the alternative minimum tax ("AMT") will count towards this 80% requirement, however, the Fund will not invest more than 5% of its net assets in securities that produce income subject to the AMT.

The Fund invests primarily in municipal bonds, municipal notes and interests in municipal leases and commercial paper issued by the governments of states, their political subdivisions (such as cities, towns and counties), the District of Columbia, or by their agencies, instrumentalities and authorities. Those securities may be "general obligation" bonds that are secured by the issuer's full faith and credit or "revenue obligations" that are payable only from a particular facility or other revenue source. The Fund can borrow money to purchase additional securities, creating "leverage" of up to one third of its total assets, as permitted under the Investment Company Act of 1940.

The Fund seeks to maintain a dollar-weighted average effective portfolio maturity between three and seven years, however, it can buy securities that have short, intermediate or long maturities. A substantial percentage of the securities the Fund buys may be "callable," meaning that the issuer can redeem them before their maturity date. Because of events affecting the bond markets and interest rate changes, the maturity of the portfolio might not meet that target for temporary periods.

The Fund will not invest more than 5% of its total assets in securities that are rated below investment grade (sometimes referred to as "junk bonds") by a nationally recognized statistical rating organization, such as Moody's Investors Service. Investment-grade securities are rated in one of the four highest rating categories of nationally recognized statistical rating organizations, such as Standard & Poor's (or, in the case of unrated securities, determined by the Fund's sub-adviser, OppenheimerFunds, Inc., to be comparable to securities rated investment-grade). The Fund will not invest more than 20% of its total assets in securities rated below the top three investment grade categories. The Fund also invests in unrated securities, in which case the Fund's sub-adviser internally assigns ratings to those securities, after assessing their credit quality and other factors, in investment-grade or below-investment-grade categories similar to those of nationally recognized statistical rating organizations. There can be no assurance, nor is it intended, that the Fund's sub-adviser's credit analysis process is consistent or comparable with the credit analysis process used by a nationally recognized statistical rating organization. The Fund will not invest more than 10% of its total assets in unrated securities. For purposes of this limitation, "unrated securities" do not include securities that are not rated but that the Fund's sub-adviser determines to be comparable to securities of the same issuer that are rated by a nationally recognized statistical rating organization.

In selecting investments for the Fund, the portfolio managers generally look for high current income; favorable credit characteristics; a wide range of issuers including different municipalities, agencies, sectors and revenue sources; unrated bonds or securities of smaller issuers that might be overlooked by other investors; and special situations that may offer high current income or opportunities for value. The portfolio managers may consider selling a security if any of these factors no longer applies, but are not required to do so.

Principal Risks. The price of the Fund's shares can go up and down substantially. The value of the Fund's investments may change because of broad changes in the markets in which the Fund invests or because of poor investment selection, which could cause the Fund to underperform other funds with similar investment objectives. There is no assurance that the Fund will achieve its investment objective. When you redeem your shares, they may be worth more or less than what you paid for them. These risks mean that you can lose money by investing in the Fund.

Main Risks of Investing in Municipal Securities. Municipal securities may be subject to interest rate risk, credit risk, credit spread risk, extension risk, reinvestment risk and prepayment risk. Interest rate risk is the risk that when prevailing interest rates fall, the values of already-issued debt securities generally rise; and when prevailing interest rates rise, the values of already-issued debt securities generally fall, and they may be worth less than the amount the Fund paid for them. When interest rates change, the values of longer-term debt securities usually change more than the values of shorter-term debt securities. Credit risk is the risk that the issuer of a security might not make interest and principal payments on the security as they become due. If an issuer fails to pay interest or repay principal, the Fund's income or share value might be reduced. Adverse news about an issuer or a downgrade in an issuer's credit rating, for any reason, can also reduce the market value of the issuer's securities. "Credit spread" is the difference in yield between securities that is due to differences in their credit quality. There is a risk that credit spreads may increase when the market expects lower-grade bonds to default more frequently. Widening credit spreads may quickly reduce the market values of the Fund's lower-rated and unrated securities. Extension risk is the risk that an increase in interest rates could cause principal payments on a debt security to be repaid at a slower rate than expected. Extension risk is particularly prevalent for a callable security where an increase in interest rates could result in the issuer of that security choosing not to redeem the security as anticipated on the security's call date. Such a decision by the issuer could have the effect of lengthening the debt security's expected maturity, making it more vulnerable to interest rate risk and reducing its market value. Reinvestment risk is the risk that when interest rates fall the Fund may be required to reinvest the proceeds from a security's sale or redemption at a lower interest rate. Callable bonds are generally subject to greater reinvestment risk than non-callable bonds. Prepayment risk is the risk that the issuer may redeem the security prior to the expected maturity or that borrowers may repay the loans that underlie these securities more quickly than expected, thereby causing the issuer of the security to repay the principal prior to the expected maturity. The Fund may need to reinvest the proceeds at a lower interest rate, reducing its income.

Municipal Market Volatility and Illiquidity. The municipal bond market can be susceptible to unusual volatility, particularly for lower-rated and unrated securities. Liquidity can be reduced unpredictably in response to overall economic conditions or credit tightening. During times of reduced market liquidity, the Fund may not be able to readily sell bonds at the prices at which they are carried on the Fund's books. If the Fund needed to sell large blocks of bonds to meet shareholder redemption requests or to raise cash, those sales could further reduce the bonds' prices.

Municipal Sector Focus Risk. While the Fund does not invest more than 25% of its total assets in a single industry, many types of municipal securities (such as general obligation, government appropriation, municipals leases, special assessment and special tax bonds) are not considered a part of any "industry" for purposes of this policy. Therefore, the Fund may invest more than 25% of its total assets in those types of municipal securities. Those municipal securities may finance or pay interest from the revenues of projects that are subject to similar economic, business or political developments that could increase their credit risk. Education, hospitals, healthcare and housing are some examples of sectors that may include similar types of projects or revenue streams. Legislation that affects the financing of a particular municipal project, or economic factors that have a negative impact on a project, would be likely to affect many other similar projects.

For example, the value of many different tobacco related bonds might be reduced if tobacco consumption decreases, if market share is lost to manufacturers who are not parties to the agreement funding the bonds, or if there is a negative outcome in litigation affecting the tobacco industry. "Land-secured" or "dirt" bonds, which are exposed to real estate risks, might lose value if developments fail to progress as anticipated or if the assessments, fees and taxes specified in project financing plans are insufficient to cover the required payments.

Taxability Risk. The Fund's investments in municipal securities rely on the opinion of the issuer's bond counsel that the interest paid on those securities will not be subject to federal income tax. Tax opinions are generally provided at the time the municipal security is initially issued. However, after the Fund buys a security, the Internal Revenue Service may determine that a bond issued as tax-exempt should in fact be taxable and the Fund's dividends with respect to that bond might be subject to federal income tax.

Risks of Non-Diversification. The Fund is classified as a "non-diversified" fund under the Investment Company Act of 1940. Accordingly, the Fund may invest a greater portion of its assets in the securities of a single issuer than if it were a "diversified" fund. To the extent that the Fund invests a higher percentage of its assets in the securities of a single issuer, the Fund is more subject to the risks associated with and developments affecting that issuer than a fund that invests more widely.

Main Risks of Borrowing and Leverage. The Fund can borrow up to one-third of the value of its assets (including the amount borrowed), as permitted under the Investment Company Act of 1940. It can use those borrowings for a number of purposes, including purchasing securities, which creates "leverage." In that case, changes in the value of the Fund's investments will have a larger effect on its share price than if it did not borrow. Borrowing results in interest payments to the lenders and related expenses. Borrowing for investment purposes might reduce the Fund's return if the yield on the securities purchased is less than those borrowing costs. The Fund may also borrow to meet redemption obligations or for temporary and emergency purposes. The Fund participates in a line of credit with other Oppenheimer funds for its borrowing.

Who Is the Fund Designed For? The Fund is designed for investors seeking income exempt from federal individual income tax. The Fund does not seek capital gains or growth. Because it invests in tax-exempt securities, the Fund is not appropriate for a retirement plan or other tax-exempt or tax-deferred account. The Fund is not a complete investment program. You should carefully consider your own investment goals and risk tolerance before investing in the Fund.

An investment in the Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

The Fund's Past Performance. 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 (for Class A shares) from year to year and by showing how the Fund's average annual returns for one year and the life of the Fund compare with those of broad measures of market performance that reflect the markets in which the Fund typically invests. The Fund's past investment performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. More recent performance information is available by calling the toll-free number on the back of this prospectus and on the Fund's website at: https://www.oppenheimerfunds.com/fund/investors/overview/RochesterIntermediateTermMunicipalFund

Sales charges and taxes are not included and the returns would be lower if they were. During the period shown, the highest return for a calendar quarter was 3.01% (2nd Qtr 11) and the lowest return was 0.13% (1st Qtr 11). For the period from January 1, 2012 to December 31, 2012 the cumulative return before sales charges and taxes was 6.38%.

Average Annual Total Returns for the periods ended December 31, 2012

The following table shows the average annual total returns for each class of the Fund's shares. After-tax returns are calculated using the highest individual federal marginal income tax rates and do not reflect the impact of state or local taxes. Your actual after-tax returns, depending on your individual tax situation, may differ from those shown and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for only one class and after-tax returns for other classes will vary.

Average Annual Total Returns (Oppenheimer Rochester® Intermediate Term Municipal Fund)	Inception Date	1 Year	5 Years (or life of class, if less)
Class A	Dec. 06, 2010	3.98%	5.14%
Class A Return After Taxes on Distributions		3.98%	5.12%
Class A Return After Taxes on Distributions and Sale of Fund Shares		3.65%	4.78%
Class C	Dec. 06, 2010	4.55%	5.40%
Class Y	Dec. 06, 2010	6.61%	6.51%
Barclays Capital Municipal Bond Index		6.78%	7.35%	[1]

[1] After discussions with the Fund's Board, the Manager has voluntarily agreed to waive fees and/or reimburse the Fund for certain expenses in order to limit "Total Annual Fund Operating Expenses," after Fee Waiver and/or Expense Reimbursement (excluding any applicable dividend expense, taxes, interest and fees from borrowing, any subsidiary expenses, Acquired Fund Fees and Expenses, brokerage commissions, extraordinary expenses and certain other fund expenses) to annual rates of 0.95% for Class A, 1.73% for Class C and 0.73% for Class Y as calculated on the daily net assets of the Fund. This fee waiver and expense limitation may not be amended or withdrawn until one year after the date of this prospectus.

[1] From 11/30/10

XML

Expense Example (dei_DocumentInformationDocumentAxis, (Oppenheimer Rochester® Intermediate Term Municipal Fund), USD $)	0 Months Ended
	Jan. 28, 2013
Class A
Expense Example:
Expense Example, with Redemption, 1 Year	$ 323
Expense Example, with Redemption, 3 Years	572
Expense Example, with Redemption, 5 Years	840
Expense Example, with Redemption, 10 Years	1,605
Class C
Expense Example:
Expense Example, with Redemption, 1 Year	280
Expense Example, with Redemption, 3 Years	638
Expense Example, with Redemption, 5 Years	1,122
Expense Example, with Redemption, 10 Years	1,978
Class Y
Expense Example:
Expense Example, with Redemption, 1 Year	78
Expense Example, with Redemption, 3 Years	300
Expense Example, with Redemption, 5 Years	541
Expense Example, with Redemption, 10 Years	$ 1,230

XML

Shareholder Fees (dei_DocumentInformationDocumentAxis, (Oppenheimer Rochester® Intermediate Term Municipal Fund))	0 Months Ended
	Jan. 28, 2013
Class A
Shareholder Fees:
Maximum Sales Charge (Load) imposed on purchases (as % of offering price)	2.25%
Maximum Deferred Sales Charge (Load) (as % of the lower of the original offering price or redemption proceeds)	none
Class C
Shareholder Fees:
Maximum Sales Charge (Load) imposed on purchases (as % of offering price)	none
Maximum Deferred Sales Charge (Load) (as % of the lower of the original offering price or redemption proceeds)	1.00%
Class Y
Shareholder Fees:
Maximum Sales Charge (Load) imposed on purchases (as % of offering price)	none
Maximum Deferred Sales Charge (Load) (as % of the lower of the original offering price or redemption proceeds)	none

XML

(Oppenheimer Rochester® Intermediate Term Municipal Fund)

Investment Objective. The Fund seeks current interest income exempt from federal individual income tax.

Fees and Expenses of the Fund. This table describes the fees and expenses that you may pay if you buy and hold or redeem shares of the Fund. You may qualify for sales charge discounts if you (or you and your spouse) invest, or agree to invest in the future, at least $100,000 in certain funds in the Oppenheimer family of funds. More information about these and other discounts is available from your financial professional and in the section "About Your Account" beginning on page 11 of the prospectus and in the sections "How to Buy Shares" beginning on page 53 and "Appendix A" in the Fund's Statement of Additional Information.

Shareholder Fees(fees paid directly from your investment)

Shareholder Fees (Oppenheimer Rochester® Intermediate Term Municipal Fund)	Class A	Class C	Class Y
Maximum Sales Charge (Load) imposed on purchases (as % of offering price)	2.25%	none	none
Maximum Deferred Sales Charge (Load) (as % of the lower of the original offering price or redemption proceeds)	none	1.00%	none

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses (Oppenheimer Rochester® Intermediate Term Municipal Fund)		Class A	Class C	Class Y
Management Fees		0.60%	0.60%	0.60%
Distribution and/or Service (12b-1) Fees		0.19%	0.99%	none
Total Other Expenses		0.38%	0.54%	0.42%
Interest and Fees from Borrowing		0.03%	0.03%	0.03%
Other Expenses		0.35%	0.51%	0.39%
Total Annual Fund Operating Expenses		1.17%	2.13%	1.02%
Fee Waiver and/or Expense Reimbursement	[1]	(0.19%)	(0.37%)	(0.26%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.98%	1.76%	0.76%

Example. The following 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 a class of shares of the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your expenses would be as follows:

If shares are redeemed

Expense Example (Oppenheimer Rochester® Intermediate Term Municipal Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	323	572	840	1,605
Class C	280	638	1,122	1,978
Class Y	78	300	541	1,230

If shares are not redeemed

Expense Example, No Redemption (Oppenheimer Rochester® Intermediate Term Municipal Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	323	572	840	1,605
Class C	180	638	1,122	1,978
Class Y	78	300	541	1,230

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 the 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 17% of the average value of its portfolio.

Principal Investment Strategies. Under normal market conditions the Fund invests at least 80% of its net assets, plus borrowings for investment purposes, in securities that pay interest that is, in the opinion of bond counsel to the issuer at the time the security is issued, exempt from federal individual income tax. Securities that generate income subject to the alternative minimum tax ("AMT") will count towards this 80% requirement, however, the Fund will not invest more than 5% of its net assets in securities that produce income subject to the AMT.

The Fund invests primarily in municipal bonds, municipal notes and interests in municipal leases and commercial paper issued by the governments of states, their political subdivisions (such as cities, towns and counties), the District of Columbia, or by their agencies, instrumentalities and authorities. Those securities may be "general obligation" bonds that are secured by the issuer's full faith and credit or "revenue obligations" that are payable only from a particular facility or other revenue source. The Fund can borrow money to purchase additional securities, creating "leverage" of up to one third of its total assets, as permitted under the Investment Company Act of 1940.

The Fund seeks to maintain a dollar-weighted average effective portfolio maturity between three and seven years, however, it can buy securities that have short, intermediate or long maturities. A substantial percentage of the securities the Fund buys may be "callable," meaning that the issuer can redeem them before their maturity date. Because of events affecting the bond markets and interest rate changes, the maturity of the portfolio might not meet that target for temporary periods.

The Fund will not invest more than 5% of its total assets in securities that are rated below investment grade (sometimes referred to as "junk bonds") by a nationally recognized statistical rating organization, such as Moody's Investors Service. Investment-grade securities are rated in one of the four highest rating categories of nationally recognized statistical rating organizations, such as Standard & Poor's (or, in the case of unrated securities, determined by the Fund's sub-adviser, OppenheimerFunds, Inc., to be comparable to securities rated investment-grade). The Fund will not invest more than 20% of its total assets in securities rated below the top three investment grade categories. The Fund also invests in unrated securities, in which case the Fund's sub-adviser internally assigns ratings to those securities, after assessing their credit quality and other factors, in investment-grade or below-investment-grade categories similar to those of nationally recognized statistical rating organizations. There can be no assurance, nor is it intended, that the Fund's sub-adviser's credit analysis process is consistent or comparable with the credit analysis process used by a nationally recognized statistical rating organization. The Fund will not invest more than 10% of its total assets in unrated securities. For purposes of this limitation, "unrated securities" do not include securities that are not rated but that the Fund's sub-adviser determines to be comparable to securities of the same issuer that are rated by a nationally recognized statistical rating organization.

In selecting investments for the Fund, the portfolio managers generally look for high current income; favorable credit characteristics; a wide range of issuers including different municipalities, agencies, sectors and revenue sources; unrated bonds or securities of smaller issuers that might be overlooked by other investors; and special situations that may offer high current income or opportunities for value. The portfolio managers may consider selling a security if any of these factors no longer applies, but are not required to do so.

Principal Risks. The price of the Fund's shares can go up and down substantially. The value of the Fund's investments may change because of broad changes in the markets in which the Fund invests or because of poor investment selection, which could cause the Fund to underperform other funds with similar investment objectives. There is no assurance that the Fund will achieve its investment objective. When you redeem your shares, they may be worth more or less than what you paid for them. These risks mean that you can lose money by investing in the Fund.

Main Risks of Investing in Municipal Securities. Municipal securities may be subject to interest rate risk, credit risk, credit spread risk, extension risk, reinvestment risk and prepayment risk. Interest rate risk is the risk that when prevailing interest rates fall, the values of already-issued debt securities generally rise; and when prevailing interest rates rise, the values of already-issued debt securities generally fall, and they may be worth less than the amount the Fund paid for them. When interest rates change, the values of longer-term debt securities usually change more than the values of shorter-term debt securities. Credit risk is the risk that the issuer of a security might not make interest and principal payments on the security as they become due. If an issuer fails to pay interest or repay principal, the Fund's income or share value might be reduced. Adverse news about an issuer or a downgrade in an issuer's credit rating, for any reason, can also reduce the market value of the issuer's securities. "Credit spread" is the difference in yield between securities that is due to differences in their credit quality. There is a risk that credit spreads may increase when the market expects lower-grade bonds to default more frequently. Widening credit spreads may quickly reduce the market values of the Fund's lower-rated and unrated securities. Extension risk is the risk that an increase in interest rates could cause principal payments on a debt security to be repaid at a slower rate than expected. Extension risk is particularly prevalent for a callable security where an increase in interest rates could result in the issuer of that security choosing not to redeem the security as anticipated on the security's call date. Such a decision by the issuer could have the effect of lengthening the debt security's expected maturity, making it more vulnerable to interest rate risk and reducing its market value. Reinvestment risk is the risk that when interest rates fall the Fund may be required to reinvest the proceeds from a security's sale or redemption at a lower interest rate. Callable bonds are generally subject to greater reinvestment risk than non-callable bonds. Prepayment risk is the risk that the issuer may redeem the security prior to the expected maturity or that borrowers may repay the loans that underlie these securities more quickly than expected, thereby causing the issuer of the security to repay the principal prior to the expected maturity. The Fund may need to reinvest the proceeds at a lower interest rate, reducing its income.

Municipal Market Volatility and Illiquidity. The municipal bond market can be susceptible to unusual volatility, particularly for lower-rated and unrated securities. Liquidity can be reduced unpredictably in response to overall economic conditions or credit tightening. During times of reduced market liquidity, the Fund may not be able to readily sell bonds at the prices at which they are carried on the Fund's books. If the Fund needed to sell large blocks of bonds to meet shareholder redemption requests or to raise cash, those sales could further reduce the bonds' prices.

Municipal Sector Focus Risk. While the Fund does not invest more than 25% of its total assets in a single industry, many types of municipal securities (such as general obligation, government appropriation, municipals leases, special assessment and special tax bonds) are not considered a part of any "industry" for purposes of this policy. Therefore, the Fund may invest more than 25% of its total assets in those types of municipal securities. Those municipal securities may finance or pay interest from the revenues of projects that are subject to similar economic, business or political developments that could increase their credit risk. Education, hospitals, healthcare and housing are some examples of sectors that may include similar types of projects or revenue streams. Legislation that affects the financing of a particular municipal project, or economic factors that have a negative impact on a project, would be likely to affect many other similar projects.

For example, the value of many different tobacco related bonds might be reduced if tobacco consumption decreases, if market share is lost to manufacturers who are not parties to the agreement funding the bonds, or if there is a negative outcome in litigation affecting the tobacco industry. "Land-secured" or "dirt" bonds, which are exposed to real estate risks, might lose value if developments fail to progress as anticipated or if the assessments, fees and taxes specified in project financing plans are insufficient to cover the required payments.

Taxability Risk. The Fund's investments in municipal securities rely on the opinion of the issuer's bond counsel that the interest paid on those securities will not be subject to federal income tax. Tax opinions are generally provided at the time the municipal security is initially issued. However, after the Fund buys a security, the Internal Revenue Service may determine that a bond issued as tax-exempt should in fact be taxable and the Fund's dividends with respect to that bond might be subject to federal income tax.

Risks of Non-Diversification. The Fund is classified as a "non-diversified" fund under the Investment Company Act of 1940. Accordingly, the Fund may invest a greater portion of its assets in the securities of a single issuer than if it were a "diversified" fund. To the extent that the Fund invests a higher percentage of its assets in the securities of a single issuer, the Fund is more subject to the risks associated with and developments affecting that issuer than a fund that invests more widely.

Main Risks of Borrowing and Leverage. The Fund can borrow up to one-third of the value of its assets (including the amount borrowed), as permitted under the Investment Company Act of 1940. It can use those borrowings for a number of purposes, including purchasing securities, which creates "leverage." In that case, changes in the value of the Fund's investments will have a larger effect on its share price than if it did not borrow. Borrowing results in interest payments to the lenders and related expenses. Borrowing for investment purposes might reduce the Fund's return if the yield on the securities purchased is less than those borrowing costs. The Fund may also borrow to meet redemption obligations or for temporary and emergency purposes. The Fund participates in a line of credit with other Oppenheimer funds for its borrowing.

Who Is the Fund Designed For? The Fund is designed for investors seeking income exempt from federal individual income tax. The Fund does not seek capital gains or growth. Because it invests in tax-exempt securities, the Fund is not appropriate for a retirement plan or other tax-exempt or tax-deferred account. The Fund is not a complete investment program. You should carefully consider your own investment goals and risk tolerance before investing in the Fund.

An investment in the Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

The Fund's Past Performance. 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 (for Class A shares) from year to year and by showing how the Fund's average annual returns for one year and the life of the Fund compare with those of broad measures of market performance that reflect the markets in which the Fund typically invests. The Fund's past investment performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. More recent performance information is available by calling the toll-free number on the back of this prospectus and on the Fund's website at: https://www.oppenheimerfunds.com/fund/investors/overview/RochesterIntermediateTermMunicipalFund

Sales charges and taxes are not included and the returns would be lower if they were. During the period shown, the highest return for a calendar quarter was 3.01% (2nd Qtr 11) and the lowest return was 0.13% (1st Qtr 11). For the period from January 1, 2012 to December 31, 2012 the cumulative return before sales charges and taxes was 6.38%.

Average Annual Total Returns for the periods ended December 31, 2012

The following table shows the average annual total returns for each class of the Fund's shares. After-tax returns are calculated using the highest individual federal marginal income tax rates and do not reflect the impact of state or local taxes. Your actual after-tax returns, depending on your individual tax situation, may differ from those shown and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for only one class and after-tax returns for other classes will vary.

Average Annual Total Returns (Oppenheimer Rochester® Intermediate Term Municipal Fund)	Inception Date	1 Year	5 Years (or life of class, if less)
Class A	Dec. 06, 2010	3.98%	5.14%
Class A Return After Taxes on Distributions		3.98%	5.12%
Class A Return After Taxes on Distributions and Sale of Fund Shares		3.65%	4.78%
Class C	Dec. 06, 2010	4.55%	5.40%
Class Y	Dec. 06, 2010	6.61%	6.51%
Barclays Capital Municipal Bond Index		6.78%	7.35%	[1]

[1] After discussions with the Fund's Board, the Manager has voluntarily agreed to waive fees and/or reimburse the Fund for certain expenses in order to limit "Total Annual Fund Operating Expenses," after Fee Waiver and/or Expense Reimbursement (excluding any applicable dividend expense, taxes, interest and fees from borrowing, any subsidiary expenses, Acquired Fund Fees and Expenses, brokerage commissions, extraordinary expenses and certain other fund expenses) to annual rates of 0.95% for Class A, 1.73% for Class C and 0.73% for Class Y as calculated on the daily net assets of the Fund. This fee waiver and expense limitation may not be amended or withdrawn until one year after the date of this prospectus.

[1] From 11/30/10

XML

Annual Total Returns (dei_DocumentInformationDocumentAxis, (Oppenheimer Rochester® Intermediate Term Municipal Fund), Class A)	0 Months Ended
	Jan. 28, 2013
(Oppenheimer Rochester® Intermediate Term Municipal Fund) | Class A
Bar Chart Table:
Annual Return 2011	7.56%
Annual Return 2012	6.38%

XML

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Document Type

dei_DocumentType

485BPOS

Document Period End Date

dei_DocumentPeriodEndDate

Sep. 30, 2012

Registrant Name

dei_EntityRegistrantName

OPPENHEIMER ROCHESTER INTERMEDIATE TERM MUNICIPAL FUND

Central Index Key

dei_EntityCentralIndexKey

0001417386

Amendment Flag

dei_AmendmentFlag

false

Document Creation Date

dei_DocumentCreationDate

Jan. 25, 2013

Document Effective Date

dei_DocumentEffectiveDate

Jan. 28, 2013

Prospectus Date

rr_ProspectusDate

Jan. 28, 2013

(Oppenheimer Rochester® Intermediate Term Municipal Fund)

Risk/Return:

rr_RiskReturnAbstract

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

Investment Objective. The Fund seeks current interest income exempt from federal individual income tax.

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

Fees and Expenses of the Fund. This table describes the fees and expenses that you may pay if you buy and hold or redeem shares of the Fund. You may qualify for sales charge discounts if you (or you and your spouse) invest, or agree to invest in the future, at least $100,000 in certain funds in the Oppenheimer family of funds. More information about these and other discounts is available from your financial professional and in the section "About Your Account" beginning on page 11 of the prospectus and in the sections "How to Buy Shares" beginning on page 53 and "Appendix A" in the Fund's Statement of Additional Information.

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 [Text Block]

rr_PortfolioTurnoverTextBlock

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 the 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 17% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

17.00%

Expense Breakpoint Discounts [Text]

rr_ExpenseBreakpointDiscounts

You may qualify for sales charge discounts if you (or you and your spouse) invest, or agree to invest in the future, at least $100,000 in certain funds in the Oppenheimer family of funds.

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

100,000

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

Example. The following 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 a class of shares of the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your expenses would be as follows:

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

If shares are redeemed

Expense Example, No Redemption, By Year, Caption [Text]

rr_ExpenseExampleNoRedemptionByYearCaption

If shares are not redeemed

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

Principal Investment Strategies. Under normal market conditions the Fund invests at least 80% of its net assets, plus borrowings for investment purposes, in securities that pay interest that is, in the opinion of bond counsel to the issuer at the time the security is issued, exempt from federal individual income tax. Securities that generate income subject to the alternative minimum tax ("AMT") will count towards this 80% requirement, however, the Fund will not invest more than 5% of its net assets in securities that produce income subject to the AMT.

The Fund invests primarily in municipal bonds, municipal notes and interests in municipal leases and commercial paper issued by the governments of states, their political subdivisions (such as cities, towns and counties), the District of Columbia, or by their agencies, instrumentalities and authorities. Those securities may be "general obligation" bonds that are secured by the issuer's full faith and credit or "revenue obligations" that are payable only from a particular facility or other revenue source. The Fund can borrow money to purchase additional securities, creating "leverage" of up to one third of its total assets, as permitted under the Investment Company Act of 1940.

The Fund seeks to maintain a dollar-weighted average effective portfolio maturity between three and seven years, however, it can buy securities that have short, intermediate or long maturities. A substantial percentage of the securities the Fund buys may be "callable," meaning that the issuer can redeem them before their maturity date. Because of events affecting the bond markets and interest rate changes, the maturity of the portfolio might not meet that target for temporary periods.

The Fund will not invest more than 5% of its total assets in securities that are rated below investment grade (sometimes referred to as "junk bonds") by a nationally recognized statistical rating organization, such as Moody's Investors Service. Investment-grade securities are rated in one of the four highest rating categories of nationally recognized statistical rating organizations, such as Standard & Poor's (or, in the case of unrated securities, determined by the Fund's sub-adviser, OppenheimerFunds, Inc., to be comparable to securities rated investment-grade). The Fund will not invest more than 20% of its total assets in securities rated below the top three investment grade categories. The Fund also invests in unrated securities, in which case the Fund's sub-adviser internally assigns ratings to those securities, after assessing their credit quality and other factors, in investment-grade or below-investment-grade categories similar to those of nationally recognized statistical rating organizations. There can be no assurance, nor is it intended, that the Fund's sub-adviser's credit analysis process is consistent or comparable with the credit analysis process used by a nationally recognized statistical rating organization. The Fund will not invest more than 10% of its total assets in unrated securities. For purposes of this limitation, "unrated securities" do not include securities that are not rated but that the Fund's sub-adviser determines to be comparable to securities of the same issuer that are rated by a nationally recognized statistical rating organization.

In selecting investments for the Fund, the portfolio managers generally look for high current income; favorable credit characteristics; a wide range of issuers including different municipalities, agencies, sectors and revenue sources; unrated bonds or securities of smaller issuers that might be overlooked by other investors; and special situations that may offer high current income or opportunities for value. The portfolio managers may consider selling a security if any of these factors no longer applies, but are not required to do so.

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

Principal Risks. The price of the Fund's shares can go up and down substantially. The value of the Fund's investments may change because of broad changes in the markets in which the Fund invests or because of poor investment selection, which could cause the Fund to underperform other funds with similar investment objectives. There is no assurance that the Fund will achieve its investment objective. When you redeem your shares, they may be worth more or less than what you paid for them. These risks mean that you can lose money by investing in the Fund.

Main Risks of Investing in Municipal Securities. Municipal securities may be subject to interest rate risk, credit risk, credit spread risk, extension risk, reinvestment risk and prepayment risk. Interest rate risk is the risk that when prevailing interest rates fall, the values of already-issued debt securities generally rise; and when prevailing interest rates rise, the values of already-issued debt securities generally fall, and they may be worth less than the amount the Fund paid for them. When interest rates change, the values of longer-term debt securities usually change more than the values of shorter-term debt securities. Credit risk is the risk that the issuer of a security might not make interest and principal payments on the security as they become due. If an issuer fails to pay interest or repay principal, the Fund's income or share value might be reduced. Adverse news about an issuer or a downgrade in an issuer's credit rating, for any reason, can also reduce the market value of the issuer's securities. "Credit spread" is the difference in yield between securities that is due to differences in their credit quality. There is a risk that credit spreads may increase when the market expects lower-grade bonds to default more frequently. Widening credit spreads may quickly reduce the market values of the Fund's lower-rated and unrated securities. Extension risk is the risk that an increase in interest rates could cause principal payments on a debt security to be repaid at a slower rate than expected. Extension risk is particularly prevalent for a callable security where an increase in interest rates could result in the issuer of that security choosing not to redeem the security as anticipated on the security's call date. Such a decision by the issuer could have the effect of lengthening the debt security's expected maturity, making it more vulnerable to interest rate risk and reducing its market value. Reinvestment risk is the risk that when interest rates fall the Fund may be required to reinvest the proceeds from a security's sale or redemption at a lower interest rate. Callable bonds are generally subject to greater reinvestment risk than non-callable bonds. Prepayment risk is the risk that the issuer may redeem the security prior to the expected maturity or that borrowers may repay the loans that underlie these securities more quickly than expected, thereby causing the issuer of the security to repay the principal prior to the expected maturity. The Fund may need to reinvest the proceeds at a lower interest rate, reducing its income.

Municipal Market Volatility and Illiquidity. The municipal bond market can be susceptible to unusual volatility, particularly for lower-rated and unrated securities. Liquidity can be reduced unpredictably in response to overall economic conditions or credit tightening. During times of reduced market liquidity, the Fund may not be able to readily sell bonds at the prices at which they are carried on the Fund's books. If the Fund needed to sell large blocks of bonds to meet shareholder redemption requests or to raise cash, those sales could further reduce the bonds' prices.

Municipal Sector Focus Risk. While the Fund does not invest more than 25% of its total assets in a single industry, many types of municipal securities (such as general obligation, government appropriation, municipals leases, special assessment and special tax bonds) are not considered a part of any "industry" for purposes of this policy. Therefore, the Fund may invest more than 25% of its total assets in those types of municipal securities. Those municipal securities may finance or pay interest from the revenues of projects that are subject to similar economic, business or political developments that could increase their credit risk. Education, hospitals, healthcare and housing are some examples of sectors that may include similar types of projects or revenue streams. Legislation that affects the financing of a particular municipal project, or economic factors that have a negative impact on a project, would be likely to affect many other similar projects.

For example, the value of many different tobacco related bonds might be reduced if tobacco consumption decreases, if market share is lost to manufacturers who are not parties to the agreement funding the bonds, or if there is a negative outcome in litigation affecting the tobacco industry. "Land-secured" or "dirt" bonds, which are exposed to real estate risks, might lose value if developments fail to progress as anticipated or if the assessments, fees and taxes specified in project financing plans are insufficient to cover the required payments.

Taxability Risk. The Fund's investments in municipal securities rely on the opinion of the issuer's bond counsel that the interest paid on those securities will not be subject to federal income tax. Tax opinions are generally provided at the time the municipal security is initially issued. However, after the Fund buys a security, the Internal Revenue Service may determine that a bond issued as tax-exempt should in fact be taxable and the Fund's dividends with respect to that bond might be subject to federal income tax.

Risks of Non-Diversification. The Fund is classified as a "non-diversified" fund under the Investment Company Act of 1940. Accordingly, the Fund may invest a greater portion of its assets in the securities of a single issuer than if it were a "diversified" fund. To the extent that the Fund invests a higher percentage of its assets in the securities of a single issuer, the Fund is more subject to the risks associated with and developments affecting that issuer than a fund that invests more widely.

Main Risks of Borrowing and Leverage. The Fund can borrow up to one-third of the value of its assets (including the amount borrowed), as permitted under the Investment Company Act of 1940. It can use those borrowings for a number of purposes, including purchasing securities, which creates "leverage." In that case, changes in the value of the Fund's investments will have a larger effect on its share price than if it did not borrow. Borrowing results in interest payments to the lenders and related expenses. Borrowing for investment purposes might reduce the Fund's return if the yield on the securities purchased is less than those borrowing costs. The Fund may also borrow to meet redemption obligations or for temporary and emergency purposes. The Fund participates in a line of credit with other Oppenheimer funds for its borrowing.

Who Is the Fund Designed For? The Fund is designed for investors seeking income exempt from federal individual income tax. The Fund does not seek capital gains or growth. Because it invests in tax-exempt securities, the Fund is not appropriate for a retirement plan or other tax-exempt or tax-deferred account. The Fund is not a complete investment program. You should carefully consider your own investment goals and risk tolerance before investing in the Fund.

An investment in the Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Risk Lose Money [Text]

rr_RiskLoseMoney

The price of the Fund's shares can go up and down substantially. The value of the Fund's investments may change because of broad changes in the markets in which the Fund invests or because of poor investment selection, which could cause the Fund to underperform other funds with similar investment objectives. There is no assurance that the Fund will achieve its investment objective. When you redeem your shares, they may be worth more or less than what you paid for them. These risks mean that you can lose money by investing in the Fund.

Risk Nondiversified Status [Text]

rr_RiskNondiversifiedStatus

Risks of Non-Diversification. The Fund is classified as a "non-diversified" fund under the Investment Company Act of 1940. Accordingly, the Fund may invest a greater portion of its assets in the securities of a single issuer than if it were a "diversified" fund. To the extent that the Fund invests a higher percentage of its assets in the securities of a single issuer, the Fund is more subject to the risks associated with and developments affecting that issuer than a fund that invests more widely.

Risk Not Insured Depository Institution [Text]

rr_RiskNotInsuredDepositoryInstitution

An investment in the Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The Fund's Past Performance. 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 (for Class A shares) from year to year and by showing how the Fund's average annual returns for one year and the life of the Fund compare with those of broad measures of market performance that reflect the markets in which the Fund typically invests. The Fund's past investment performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. More recent performance information is available by calling the toll-free number on the back of this prospectus and on the Fund's website at: https://www.oppenheimerfunds.com/fund/investors/overview/RochesterIntermediateTermMunicipalFund

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

https://www.oppenheimerfunds.com/fund/investors/overview/RochesterIntermediateTermMunicipalFund

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

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

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Sales charges and taxes are not included and the returns would be lower if they were. During the period shown, the highest return for a calendar quarter was 3.01% (2nd Qtr 11) and the lowest return was 0.13% (1st Qtr 11). For the period from January 1, 2012 to December 31, 2012 the cumulative return before sales charges and taxes was 6.38%.

Performance Table Heading

rr_PerformanceTableHeading

Average Annual Total Returns for the periods ended December 31, 2012

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the highest individual federal marginal income tax rates and do not reflect the impact of state or local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Your actual after-tax returns, depending on your individual tax situation, may differ from those shown and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax returns are shown for only one class and after-tax returns for other classes will vary.

Performance Table Narrative

rr_PerformanceTableNarrativeTextBlock

The following table shows the average annual total returns for each class of the Fund's shares. After-tax returns are calculated using the highest individual federal marginal income tax rates and do not reflect the impact of state or local taxes. Your actual after-tax returns, depending on your individual tax situation, may differ from those shown and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for only one class and after-tax returns for other classes will vary.

(Oppenheimer Rochester® Intermediate Term Municipal Fund) | Barclays Capital Municipal Bond Index

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

6.78%

5 Years (or life of class, if less)

rr_AverageAnnualReturnYear05

7.35%

^[2]

(Oppenheimer Rochester® Intermediate Term Municipal Fund) | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge (Load) imposed on purchases (as % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

2.25%

Maximum Deferred Sales Charge (Load) (as % of the lower of the original offering price or redemption proceeds)

rr_MaximumDeferredSalesChargeOverOther

none

Management Fees

rr_ManagementFeesOverAssets

0.60%

Distribution and/or Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.19%

Interest and Fees from Borrowing

rr_Component1OtherExpensesOverAssets

0.03%

Other Expenses

rr_Component2OtherExpensesOverAssets

0.35%

Total Other Expenses

rr_OtherExpensesOverAssets

0.38%

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

1.17%

Fee Waiver and/or Expense Reimbursement

rr_FeeWaiverOrReimbursementOverAssets

(0.19%)

^[1]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.98%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

323

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

572

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

840

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,605

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

323

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

572

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

840

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

1,605

Annual Return 2011

rr_AnnualReturn2011

7.56%

Annual Return 2012

rr_AnnualReturn2012

6.38%

Year to Date Return, Label

rr_YearToDateReturnLabel

For the period from January 1, 2012 to December 31, 2012 the cumulative return before sales charges and taxes was 6.38%.

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Dec. 31, 2012

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

6.38%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

highest return for a calendar quarter was 3.01% (2nd Qtr 11)

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

3.01%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

lowest return was 0.13% (1st Qtr 11)

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

0.13%

1 Year

rr_AverageAnnualReturnYear01

3.98%

5 Years (or life of class, if less)

rr_AverageAnnualReturnYear05

5.14%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 06, 2010

(Oppenheimer Rochester® Intermediate Term Municipal Fund) | Class A | Return After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

3.98%

5 Years (or life of class, if less)

rr_AverageAnnualReturnYear05

5.12%

(Oppenheimer Rochester® Intermediate Term Municipal Fund) | Class A | Return After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

3.65%

5 Years (or life of class, if less)

rr_AverageAnnualReturnYear05

4.78%

(Oppenheimer Rochester® Intermediate Term Municipal Fund) | Class C

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge (Load) imposed on purchases (as % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge (Load) (as % of the lower of the original offering price or redemption proceeds)

rr_MaximumDeferredSalesChargeOverOther

1.00%

Management Fees

rr_ManagementFeesOverAssets

0.60%

Distribution and/or Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.99%

Interest and Fees from Borrowing

rr_Component1OtherExpensesOverAssets

0.03%

Other Expenses

rr_Component2OtherExpensesOverAssets

0.51%

Total Other Expenses

rr_OtherExpensesOverAssets

0.54%

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

2.13%

Fee Waiver and/or Expense Reimbursement

rr_FeeWaiverOrReimbursementOverAssets

(0.37%)

^[1]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

1.76%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

280

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

638

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,122

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,978

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

180

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

638

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

1,122

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

1,978

1 Year

rr_AverageAnnualReturnYear01

4.55%

5 Years (or life of class, if less)

rr_AverageAnnualReturnYear05

5.40%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 06, 2010

(Oppenheimer Rochester® Intermediate Term Municipal Fund) | Class Y

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge (Load) imposed on purchases (as % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge (Load) (as % of the lower of the original offering price or redemption proceeds)

rr_MaximumDeferredSalesChargeOverOther

none

Management Fees

rr_ManagementFeesOverAssets

0.60%

Distribution and/or Service (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

Interest and Fees from Borrowing

rr_Component1OtherExpensesOverAssets

0.03%

Other Expenses

rr_Component2OtherExpensesOverAssets

0.39%

Total Other Expenses

rr_OtherExpensesOverAssets

0.42%

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

1.02%

Fee Waiver and/or Expense Reimbursement

rr_FeeWaiverOrReimbursementOverAssets

(0.26%)

^[1]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.76%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

78

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

300

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

541

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,230

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

78

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

300

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

541

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

1,230

1 Year

rr_AverageAnnualReturnYear01

6.61%

5 Years (or life of class, if less)

rr_AverageAnnualReturnYear05

6.51%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 06, 2010

[1] After discussions with the Fund's Board, the Manager has voluntarily agreed to waive fees and/or reimburse the Fund for certain expenses in order to limit "Total Annual Fund Operating Expenses," after Fee Waiver and/or Expense Reimbursement (excluding any applicable dividend expense, taxes, interest and fees from borrowing, any subsidiary expenses, Acquired Fund Fees and Expenses, brokerage commissions, extraordinary expenses and certain other fund expenses) to annual rates of 0.95% for Class A, 1.73% for Class C and 0.73% for Class Y as calculated on the daily net assets of the Fund. This fee waiver and expense limitation may not be amended or withdrawn until one year after the date of this prospectus.

[2] From 11/30/10