485BPOS

Registration No. 2-91683

File No. 811-4054

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. 44	x
and/or
REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940	x
Amendment No. 43	x

OPPENHEIMER ROCHESTER AMT-FREE NEW YORK 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 11^th Floor, 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 on the 11th day of February, 2013.

OPPENHEIMER ROCHESTER AMT-FREE NEW YORK MUNICIPAL FUND
By:	William F. Glavin, Jr.*
	William F. Glavin, Jr., President and Principal 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 on the dates indicated:

Signatures	Title	Date
Brian F. Wruble*	Chairman of the	February 11, 2013
Brian F. Wruble	Board of Trustees
William F. Glavin, Jr.*	President and Principal	February 11, 2013
William F. Glavin, Jr.	Executive Officer
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® AMT-Free New York Municipal Fund), USD $)	0 Months Ended
	Jan. 28, 2013
Class A
Expense Example, No Redemption:
Expense Example, No Redemption, 1 Year	$ 571
Expense Example, No Redemption, 3 Years	774
Expense Example, No Redemption, 5 Years	993
Expense Example, No Redemption, 10 Years	1,625
Class B
Expense Example, No Redemption:
Expense Example, No Redemption, 1 Year	189
Expense Example, No Redemption, 3 Years	584
Expense Example, No Redemption, 5 Years	1,005
Expense Example, No Redemption, 10 Years	1,739
Class C
Expense Example, No Redemption:
Expense Example, No Redemption, 1 Year	180
Expense Example, No Redemption, 3 Years	559
Expense Example, No Redemption, 5 Years	962
Expense Example, No Redemption, 10 Years	2,091
Class Y
Expense Example, No Redemption:
Expense Example, No Redemption, 1 Year	78
Expense Example, No Redemption, 3 Years	244
Expense Example, No Redemption, 5 Years	424
Expense Example, No Redemption, 10 Years	$ 946

XML

(Oppenheimer Rochester® AMT-Free New York Municipal Fund)

Investment Objective. The Fund seeks the maximum current income exempt from federal, New York State and New York City income taxes for individual investors consistent with preservation of capital.

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 $50,000 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 14 of the prospectus and in the sections "How to Buy Shares" beginning on page 56 and "Appendix A" in the Fund's Statement of Additional Information.

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees (Oppenheimer Rochester® AMT-Free New York Municipal Fund)	Class A	Class B	Class C	Class Y
Maximum Sales Charge (Load) imposed on purchases (as % of offering price)	4.75%	none	none	none
Maximum Deferred Sales Charge (Load) (as % of the lower of the original offering price or redemption proceeds)	none	5.00%	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® AMT-Free New York Municipal Fund)	Class A	Class B	Class C	Class Y
Management Fees	0.46%	0.46%	0.46%	0.46%
Disribution and/or Service (12b-1) Fees	0.24%	1.00%	1.00%	none
Total Other Expenses	0.28%	0.38%	0.30%	0.30%
Interest and Related Expenses from Inverse Floaters	0.14%	0.14%	0.14%	0.14%
Interest and Fees from Borrowing	0.09%	0.09%	0.09%	0.09%
Other Expenses	0.05%	0.15%	0.07%	0.07%
Total Annual Fund Operating Exenses	0.98%	1.84%	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® AMT-Free New York Municipal Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	571	774	993	1,625
Class B	689	884	1,205	1,739
Class C	280	559	962	2,091
Class Y	78	244	424	946

If shares are not redeemed

Expense Example, No Redemption (Oppenheimer Rochester® AMT-Free New York Municipal Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	571	774	993	1,625
Class B	189	584	1,005	1,739
Class C	180	559	962	2,091
Class Y	78	244	424	946

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 14% of the average value of its portfolio.

Principal Investment Strategies. Under normal market conditions the Fund invests at least 80% of its net assets in New York municipal securities that pay interest that, in the opinion of counsel to the issuer of each security, is exempt from federal and New York State and New York City personal income taxes (referred to as "New York municipal securities"). These primarily include municipal bonds, municipal notes, and interests in municipal leases. As a non-fundamental investment policy, the Fund will not invest in municipal securities the interest from which (and thus proportionate share of the exempt-interest dividends paid by the Fund) would be subject to the federal alternative minimum tax (AMT).

The Fund's New York municipal securities include tax-exempt debt obligations issued by the State of New York or its political subdivisions (cities, towns and counties, for example); agencies, public authorities and instrumentalities (these are state-chartered corporations) of the State of New York; and New York municipal securities also include U.S. territories, commonwealths and possessions (for example, Puerto Rico, Guam and the Virgin Islands) that pay interest that is exempt (in the opinion of the issuer's legal counsel when the security is issued) from federal income tax and New York State and New York City personal income taxes.

Most of the securities the Fund buys are "investment-grade," although it can invest as much as 25% of its total assets in below-investment-grade securities (commonly called "junk bonds"). 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 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 Sub-Adviser's credit analysis process is consistent with or comparable with the credit analysis process used by a nationally recognized statistical rating organization.

The Fund does not limit its investments to securities of a particular maturity range, but it generally focuses on longer-term securities to seek higher yields. The Fund can invest in inverse floaters, a variable rate obligation and form of derivative, to seek increased income and return. The Fund's investment in inverse floaters entails a degree of leverage. The Fund can expose up to 20% of its total assets to the effects of leverage from its investments in inverse floaters.

The Fund can borrow money to purchase additional securities, another form of leverage. Although the amount of borrowing will vary from time to time, the amount of leveraging from borrowings will not exceed one-third of the Fund's total assets.

In selecting investments for the Fund, the portfolio managers generally look at a wide range of New York municipal securities, including unrated bonds and securities of smaller issuers, from different issuers that provide high current tax-free income and might be overlooked by other investors and funds.

The portfolio managers may consider selling a security if any of these factors no longer applies to a security purchased for the Fund, 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.

Special Risks of Below-Investment-Grade Securities. Below-investment-grade debt securities may be subject to greater price fluctuations and have a greater risk that the issuer might not be able to pay interest and principal when due. The market for below-investment-grade securities may be less liquid and they may be harder to value or to sell at an acceptable price, especially during times of market volatility or decline.

Because the Fund can invest up to 25% of its assets in below-investment-grade securities, the Fund's credit risks are greater than those of funds that buy only investment-grade securities. This restriction is applied at the time of purchase and the Fund may continue to hold a security whose credit rating has been lowered or, in the case of an unrated security, after the Fund's adviser has changed its assessment of the security's credit quality. As a result, credit rating downgrades or other market fluctuations may cause the Fund's holdings of below-investment-grade securities to exceed this restriction for an extended period of time. If the Fund has more than 25% of its total assets invested in below-investment-grade securities, the adviser will not purchase additional below-investment-grade securities until the level of holdings in those securities no longer exceeds the restriction.

Special Risks of New York Municipal Securities. Because the Fund invests primarily in New York municipal securities, the value of its portfolio investments will be highly sensitive to events affecting the financial stability of the state of New York and its municipalities, agencies, authorities and other instrumentalities that issue those securities. Changes in legislation or policy, erosion of the tax base, the effects of terrorist acts or natural disasters, or other economic or credit problems may have a significant negative impact on the value of state or local securities.

These risks also apply to securities of issuers of U.S. territories, commonwealths or possessions located outside of New York such as Puerto Rico, Guam, the Northern Mariana Islands and the Virgin Islands.

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.

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 Concentration. While the Fund does not invest more than 25% of its total assets in a single industry, certain types of municipal securities (such as general obligation, government appropriation, municipal 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 these types of municipal securities. These types of municipal securities may finance, or pay interest from the revenues of, projects that tend to be impacted in the same way by economic, business or political developments which would increase credit risk. For example, legislation on the financing of a project or a declining economic need for the project would likely affect all similar projects.

Risks of Tobacco Related Bonds. In 1998, the largest U.S. tobacco manufacturers reached an out of court agreement, known as the Master Settlement Agreement (the "MSA"), to settle claims against them by 46 states and six other U.S. jurisdictions. The tobacco manufacturers agreed to make annual payments to the government entities in exchange for the release of all litigation claims. A number of the states have sold bonds that are backed by those future payments. The Fund may invest in two types of those bonds: (i) bonds that make payments only from a state's interest in the MSA and (ii) bonds that make payments from both the MSA revenue and from an "appropriation pledge" by the state. An "appropriation pledge" requires the state to pass a specific periodic appropriation to make the payments and is generally not an unconditional guarantee of payment by a state.

The settlement payments are based on factors, including, but not limited to, annual domestic cigarette shipments, cigarette consumption, inflation and the financial capability of participating tobacco companies. Payments could be reduced if consumption decreases, if market share is lost to non-MSA manufacturers, or if there is a negative outcome in litigation regarding the MSA, including challenges by participating tobacco manufacturers regarding the amount of annual payments owed under the MSA.

The Fund can invest up to 25% of its total assets in tobacco-related bonds without an appropriation pledge that make payments only from a state's interest in the MSA.

Main Risks of Borrowing and Leverage. The Fund can borrow up to one-third of the value of its total assets (including the amount borrowed) from banks, as permitted by the Investment Company Act of 1940. It can use those borrowings for a number of purposes, including for purchasing securities, which can create "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, for temporary and emergency purposes, or to unwind or contribute to trusts in connection with the Fund's investment in inverse floaters (instruments also involving the use of leverage, as discussed below). The Fund currently participates in a line of credit with other Oppenheimer funds for its borrowing.

Risks of Derivatives. A "derivative" is an investment whose value depends on (or is derived from) the value of an underlying security, asset, interest rate, index or currency. Derivatives may be volatile and involve significant risks. Derivative transactions may require the payment of premiums and can increase portfolio turnover. Certain derivative investments may be illiquid. The underlying security or other reference on which a derivative is based, or the derivative itself, may not perform the way the Fund expects it to. The Fund could realize little or no income or lose principal from a derivative investment or a hedge might be unsuccessful. The Fund may also lose money if the issuer of a derivative fails to pay the amount due.

Inverse Floaters. The Fund invests in inverse floating rate securities ("inverse floaters") because, under ordinary circumstances, they offer higher yields and thus provide higher income than fixed-rate municipal bonds of comparable maturity and credit quality. Because inverse floaters are leveraged instruments, the value of an inverse floater will change more significantly in response to changes in interest rates and other market fluctuations than the market value of a conventional fixed-rate municipal security of comparable maturity and credit quality, including the municipal bond underlying an inverse floater.

An inverse floater is created when a fixed-rate municipal bond is contributed to a trust. The trust issues two separate classes of securities: short-term floating rate securities with a fixed principal amount that represent a senior interest in the underlying municipal bond, and the inverse floater that represents a residual, subordinate interest in the underlying municipal bond. The trust issues and sells the short-term floating rate securities to third parties and the inverse floater to the Fund. The short-term floating rate securities generally bear short-term rates of interest. When interest is paid on the underlying municipal bond to the trust, such proceeds are first used to pay interest owing to holders of the short-term floating rate securities, with any remaining amounts being paid to the Fund, as the holder of the inverse floater. Accordingly, the amount of such interest paid to the Fund is inversely related to the rate of interest on the short-term floating rate securities. Inverse floaters produce less income when short-term interest rates rise (and, in extreme cases, may pay no income) and more income when short-term interest rates fall. Thus, if short-term interest rates rise after the issuance of the inverse floater, any yield advantage to the Fund is reduced and may be eliminated. Additionally, because the principal amount of the short-term floating rate security is fixed and is not adjusted in response to changes in the market value of the underlying municipal bond, any change in the market value of the underlying municipal bond is reflected entirely in a change to the value of the inverse floater. Upon the occurrence of certain adverse events, a trust may be collapsed and the underlying municipal bond liquidated, and the Fund could lose the entire amount of its investment in the inverse floater and may, in some cases, be contractually required to pay the negative difference, if any, between the liquidation value of the underlying municipal bond and the principal amount of the short-term floating rate securities.

The Fund may invest in inverse floaters with any degree of leverage (measured by comparing the outstanding principal amount of related short-term floating rate securities to the par value of the underlying municipal bond). However, the Fund may only expose up to 20% of its total assets to the effects of leverage from its investments in inverse floaters. This limitation is measured by comparing the aggregate principal amount of the short-term floating rate securities that are related to the inverse floaters held by the Fund to the total assets of the Fund. Nevertheless, the value of, and income earned on, an inverse floater that has a higher degree of leverage (represented by a larger outstanding principal amount of related short-term floating rate securities) will fluctuate more significantly in response to changes in interest rates and to changes in the market value of the related underlying municipal bond, and are more likely to be eliminated entirely under adverse market conditions.

Who Is the Fund Designed For? The Fund is designed for investors seeking income exempt from federal (including the alternative minimum tax), New York State and New York City personal income taxes. The Fund does not seek capital gains or growth. Investors should be willing to assume credit, interest rate and reinvestment risks. 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 1, 5 and 10 years compare with those of a broad measure of market performance. 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: https://www.oppenheimerfunds.com/fund/investors/overview/RochesterAMTFreeNewYorkMunicipal

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 23.97% (3rd Qtr 09) and the lowest return was -19.43% (4th Qtr 08). For the period from January 1, 2012 to December 31, 2012, the cumulative return before sales charges and taxes was 13.67%.

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® AMT-Free New York Municipal Fund)		Inception Date	1 Year	5 Years (or life of class, if less)	10 Years (or life of class, if less)
Class A		Aug. 16, 1984	8.27%	4.72%	4.93%
Class A Return After Taxes on Distributions			8.27%	4.72%	4.93%
Class A Return After Taxes on Distributions and Sale of Fund Shares			7.39%	4.79%	4.96%
Class B		Mar. 01, 1993	7.62%	4.50%	4.95%
Class C		Aug. 29, 1995	11.69%	4.91%	4.63%
Class Y		Jan. 31, 2011	13.91%	16.05%	none
Barclays Capital Municipal Bond Index			6.78%	5.91%	5.10%
Barclays Capital Municipal Bond Index (reflects no deduction for fees, expenses or taxes)	[1]			9.54%
Consumer Price Index			1.74%	1.80%	2.41%
Consumer Price Index (reflects no deduction for fees, expenses or taxes)	[1]			2.20%

[1] As of 1/31/2011

XML

Expense Example (dei_DocumentInformationDocumentAxis, (Oppenheimer Rochester® AMT-Free New York Municipal Fund), USD $)	0 Months Ended
	Jan. 28, 2013
Class A
Expense Example:
Expense Example, with Redemption, 1 Year	$ 571
Expense Example, with Redemption, 3 Years	774
Expense Example, with Redemption, 5 Years	993
Expense Example, with Redemption, 10 Years	1,625
Class B
Expense Example:
Expense Example, with Redemption, 1 Year	689
Expense Example, with Redemption, 3 Years	884
Expense Example, with Redemption, 5 Years	1,205
Expense Example, with Redemption, 10 Years	1,739
Class C
Expense Example:
Expense Example, with Redemption, 1 Year	280
Expense Example, with Redemption, 3 Years	559
Expense Example, with Redemption, 5 Years	962
Expense Example, with Redemption, 10 Years	2,091
Class Y
Expense Example:
Expense Example, with Redemption, 1 Year	78
Expense Example, with Redemption, 3 Years	244
Expense Example, with Redemption, 5 Years	424
Expense Example, with Redemption, 10 Years	$ 946

XML

Shareholder Fees (dei_DocumentInformationDocumentAxis, (Oppenheimer Rochester® AMT-Free New York Municipal Fund))	0 Months Ended
	Jan. 28, 2013
Class A
Shareholder Fees:
Maximum Sales Charge (Load) imposed on purchases (as % of offering price)	4.75%
Maximum Deferred Sales Charge (Load) (as % of the lower of the original offering price or redemption proceeds)	none
Class B
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)	5.00%
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® AMT-Free New York Municipal Fund)

Investment Objective. The Fund seeks the maximum current income exempt from federal, New York State and New York City income taxes for individual investors consistent with preservation of capital.

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 $50,000 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 14 of the prospectus and in the sections "How to Buy Shares" beginning on page 56 and "Appendix A" in the Fund's Statement of Additional Information.

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees (Oppenheimer Rochester® AMT-Free New York Municipal Fund)	Class A	Class B	Class C	Class Y
Maximum Sales Charge (Load) imposed on purchases (as % of offering price)	4.75%	none	none	none
Maximum Deferred Sales Charge (Load) (as % of the lower of the original offering price or redemption proceeds)	none	5.00%	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® AMT-Free New York Municipal Fund)	Class A	Class B	Class C	Class Y
Management Fees	0.46%	0.46%	0.46%	0.46%
Disribution and/or Service (12b-1) Fees	0.24%	1.00%	1.00%	none
Total Other Expenses	0.28%	0.38%	0.30%	0.30%
Interest and Related Expenses from Inverse Floaters	0.14%	0.14%	0.14%	0.14%
Interest and Fees from Borrowing	0.09%	0.09%	0.09%	0.09%
Other Expenses	0.05%	0.15%	0.07%	0.07%
Total Annual Fund Operating Exenses	0.98%	1.84%	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® AMT-Free New York Municipal Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	571	774	993	1,625
Class B	689	884	1,205	1,739
Class C	280	559	962	2,091
Class Y	78	244	424	946

If shares are not redeemed

Expense Example, No Redemption (Oppenheimer Rochester® AMT-Free New York Municipal Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class A	571	774	993	1,625
Class B	189	584	1,005	1,739
Class C	180	559	962	2,091
Class Y	78	244	424	946

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 14% of the average value of its portfolio.

Principal Investment Strategies. Under normal market conditions the Fund invests at least 80% of its net assets in New York municipal securities that pay interest that, in the opinion of counsel to the issuer of each security, is exempt from federal and New York State and New York City personal income taxes (referred to as "New York municipal securities"). These primarily include municipal bonds, municipal notes, and interests in municipal leases. As a non-fundamental investment policy, the Fund will not invest in municipal securities the interest from which (and thus proportionate share of the exempt-interest dividends paid by the Fund) would be subject to the federal alternative minimum tax (AMT).

The Fund's New York municipal securities include tax-exempt debt obligations issued by the State of New York or its political subdivisions (cities, towns and counties, for example); agencies, public authorities and instrumentalities (these are state-chartered corporations) of the State of New York; and New York municipal securities also include U.S. territories, commonwealths and possessions (for example, Puerto Rico, Guam and the Virgin Islands) that pay interest that is exempt (in the opinion of the issuer's legal counsel when the security is issued) from federal income tax and New York State and New York City personal income taxes.

Most of the securities the Fund buys are "investment-grade," although it can invest as much as 25% of its total assets in below-investment-grade securities (commonly called "junk bonds"). 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 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 Sub-Adviser's credit analysis process is consistent with or comparable with the credit analysis process used by a nationally recognized statistical rating organization.

The Fund does not limit its investments to securities of a particular maturity range, but it generally focuses on longer-term securities to seek higher yields. The Fund can invest in inverse floaters, a variable rate obligation and form of derivative, to seek increased income and return. The Fund's investment in inverse floaters entails a degree of leverage. The Fund can expose up to 20% of its total assets to the effects of leverage from its investments in inverse floaters.

The Fund can borrow money to purchase additional securities, another form of leverage. Although the amount of borrowing will vary from time to time, the amount of leveraging from borrowings will not exceed one-third of the Fund's total assets.

In selecting investments for the Fund, the portfolio managers generally look at a wide range of New York municipal securities, including unrated bonds and securities of smaller issuers, from different issuers that provide high current tax-free income and might be overlooked by other investors and funds.

The portfolio managers may consider selling a security if any of these factors no longer applies to a security purchased for the Fund, 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.

Special Risks of Below-Investment-Grade Securities. Below-investment-grade debt securities may be subject to greater price fluctuations and have a greater risk that the issuer might not be able to pay interest and principal when due. The market for below-investment-grade securities may be less liquid and they may be harder to value or to sell at an acceptable price, especially during times of market volatility or decline.

Because the Fund can invest up to 25% of its assets in below-investment-grade securities, the Fund's credit risks are greater than those of funds that buy only investment-grade securities. This restriction is applied at the time of purchase and the Fund may continue to hold a security whose credit rating has been lowered or, in the case of an unrated security, after the Fund's adviser has changed its assessment of the security's credit quality. As a result, credit rating downgrades or other market fluctuations may cause the Fund's holdings of below-investment-grade securities to exceed this restriction for an extended period of time. If the Fund has more than 25% of its total assets invested in below-investment-grade securities, the adviser will not purchase additional below-investment-grade securities until the level of holdings in those securities no longer exceeds the restriction.

Special Risks of New York Municipal Securities. Because the Fund invests primarily in New York municipal securities, the value of its portfolio investments will be highly sensitive to events affecting the financial stability of the state of New York and its municipalities, agencies, authorities and other instrumentalities that issue those securities. Changes in legislation or policy, erosion of the tax base, the effects of terrorist acts or natural disasters, or other economic or credit problems may have a significant negative impact on the value of state or local securities.

These risks also apply to securities of issuers of U.S. territories, commonwealths or possessions located outside of New York such as Puerto Rico, Guam, the Northern Mariana Islands and the Virgin Islands.

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.

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 Concentration. While the Fund does not invest more than 25% of its total assets in a single industry, certain types of municipal securities (such as general obligation, government appropriation, municipal 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 these types of municipal securities. These types of municipal securities may finance, or pay interest from the revenues of, projects that tend to be impacted in the same way by economic, business or political developments which would increase credit risk. For example, legislation on the financing of a project or a declining economic need for the project would likely affect all similar projects.

Risks of Tobacco Related Bonds. In 1998, the largest U.S. tobacco manufacturers reached an out of court agreement, known as the Master Settlement Agreement (the "MSA"), to settle claims against them by 46 states and six other U.S. jurisdictions. The tobacco manufacturers agreed to make annual payments to the government entities in exchange for the release of all litigation claims. A number of the states have sold bonds that are backed by those future payments. The Fund may invest in two types of those bonds: (i) bonds that make payments only from a state's interest in the MSA and (ii) bonds that make payments from both the MSA revenue and from an "appropriation pledge" by the state. An "appropriation pledge" requires the state to pass a specific periodic appropriation to make the payments and is generally not an unconditional guarantee of payment by a state.

The settlement payments are based on factors, including, but not limited to, annual domestic cigarette shipments, cigarette consumption, inflation and the financial capability of participating tobacco companies. Payments could be reduced if consumption decreases, if market share is lost to non-MSA manufacturers, or if there is a negative outcome in litigation regarding the MSA, including challenges by participating tobacco manufacturers regarding the amount of annual payments owed under the MSA.

The Fund can invest up to 25% of its total assets in tobacco-related bonds without an appropriation pledge that make payments only from a state's interest in the MSA.

Main Risks of Borrowing and Leverage. The Fund can borrow up to one-third of the value of its total assets (including the amount borrowed) from banks, as permitted by the Investment Company Act of 1940. It can use those borrowings for a number of purposes, including for purchasing securities, which can create "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, for temporary and emergency purposes, or to unwind or contribute to trusts in connection with the Fund's investment in inverse floaters (instruments also involving the use of leverage, as discussed below). The Fund currently participates in a line of credit with other Oppenheimer funds for its borrowing.

Risks of Derivatives. A "derivative" is an investment whose value depends on (or is derived from) the value of an underlying security, asset, interest rate, index or currency. Derivatives may be volatile and involve significant risks. Derivative transactions may require the payment of premiums and can increase portfolio turnover. Certain derivative investments may be illiquid. The underlying security or other reference on which a derivative is based, or the derivative itself, may not perform the way the Fund expects it to. The Fund could realize little or no income or lose principal from a derivative investment or a hedge might be unsuccessful. The Fund may also lose money if the issuer of a derivative fails to pay the amount due.

Inverse Floaters. The Fund invests in inverse floating rate securities ("inverse floaters") because, under ordinary circumstances, they offer higher yields and thus provide higher income than fixed-rate municipal bonds of comparable maturity and credit quality. Because inverse floaters are leveraged instruments, the value of an inverse floater will change more significantly in response to changes in interest rates and other market fluctuations than the market value of a conventional fixed-rate municipal security of comparable maturity and credit quality, including the municipal bond underlying an inverse floater.

An inverse floater is created when a fixed-rate municipal bond is contributed to a trust. The trust issues two separate classes of securities: short-term floating rate securities with a fixed principal amount that represent a senior interest in the underlying municipal bond, and the inverse floater that represents a residual, subordinate interest in the underlying municipal bond. The trust issues and sells the short-term floating rate securities to third parties and the inverse floater to the Fund. The short-term floating rate securities generally bear short-term rates of interest. When interest is paid on the underlying municipal bond to the trust, such proceeds are first used to pay interest owing to holders of the short-term floating rate securities, with any remaining amounts being paid to the Fund, as the holder of the inverse floater. Accordingly, the amount of such interest paid to the Fund is inversely related to the rate of interest on the short-term floating rate securities. Inverse floaters produce less income when short-term interest rates rise (and, in extreme cases, may pay no income) and more income when short-term interest rates fall. Thus, if short-term interest rates rise after the issuance of the inverse floater, any yield advantage to the Fund is reduced and may be eliminated. Additionally, because the principal amount of the short-term floating rate security is fixed and is not adjusted in response to changes in the market value of the underlying municipal bond, any change in the market value of the underlying municipal bond is reflected entirely in a change to the value of the inverse floater. Upon the occurrence of certain adverse events, a trust may be collapsed and the underlying municipal bond liquidated, and the Fund could lose the entire amount of its investment in the inverse floater and may, in some cases, be contractually required to pay the negative difference, if any, between the liquidation value of the underlying municipal bond and the principal amount of the short-term floating rate securities.

The Fund may invest in inverse floaters with any degree of leverage (measured by comparing the outstanding principal amount of related short-term floating rate securities to the par value of the underlying municipal bond). However, the Fund may only expose up to 20% of its total assets to the effects of leverage from its investments in inverse floaters. This limitation is measured by comparing the aggregate principal amount of the short-term floating rate securities that are related to the inverse floaters held by the Fund to the total assets of the Fund. Nevertheless, the value of, and income earned on, an inverse floater that has a higher degree of leverage (represented by a larger outstanding principal amount of related short-term floating rate securities) will fluctuate more significantly in response to changes in interest rates and to changes in the market value of the related underlying municipal bond, and are more likely to be eliminated entirely under adverse market conditions.

Who Is the Fund Designed For? The Fund is designed for investors seeking income exempt from federal (including the alternative minimum tax), New York State and New York City personal income taxes. The Fund does not seek capital gains or growth. Investors should be willing to assume credit, interest rate and reinvestment risks. 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 1, 5 and 10 years compare with those of a broad measure of market performance. 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: https://www.oppenheimerfunds.com/fund/investors/overview/RochesterAMTFreeNewYorkMunicipal

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 23.97% (3rd Qtr 09) and the lowest return was -19.43% (4th Qtr 08). For the period from January 1, 2012 to December 31, 2012, the cumulative return before sales charges and taxes was 13.67%.

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® AMT-Free New York Municipal Fund)		Inception Date	1 Year	5 Years (or life of class, if less)	10 Years (or life of class, if less)
Class A		Aug. 16, 1984	8.27%	4.72%	4.93%
Class A Return After Taxes on Distributions			8.27%	4.72%	4.93%
Class A Return After Taxes on Distributions and Sale of Fund Shares			7.39%	4.79%	4.96%
Class B		Mar. 01, 1993	7.62%	4.50%	4.95%
Class C		Aug. 29, 1995	11.69%	4.91%	4.63%
Class Y		Jan. 31, 2011	13.91%	16.05%	none
Barclays Capital Municipal Bond Index			6.78%	5.91%	5.10%
Barclays Capital Municipal Bond Index (reflects no deduction for fees, expenses or taxes)	[1]			9.54%
Consumer Price Index			1.74%	1.80%	2.41%
Consumer Price Index (reflects no deduction for fees, expenses or taxes)	[1]			2.20%

[1] As of 1/31/2011

XML

Annual Total Returns (dei_DocumentInformationDocumentAxis, (Oppenheimer Rochester® AMT-Free New York Municipal Fund), Class A)	0 Months Ended
	Jan. 28, 2013
(Oppenheimer Rochester® AMT-Free New York Municipal Fund) | Class A
Bar Chart Table:
Annual Return 2003	6.95%
Annual Return 2004	4.38%
Annual Return 2005	8.08%
Annual Return 2006	8.76%
Annual Return 2007	(2.04%)
Annual Return 2008	(29.02%)
Annual Return 2009	41.44%
Annual Return 2010	2.44%
Annual Return 2011	13.08%
Annual Return 2012	13.67%

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 AMT-FREE NEW YORK MUNICIPAL FUND

Central Index Key

dei_EntityCentralIndexKey

0000748009

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® AMT-Free New York Municipal Fund)

Risk/Return:

rr_RiskReturnAbstract

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

Investment Objective. The Fund seeks the maximum current income exempt from federal, New York State and New York City income taxes for individual investors consistent with preservation of capital.

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 $50,000 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 14 of the prospectus and in the sections "How to Buy Shares" beginning on page 56 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 14% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

14.00%

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 $50,000 in certain funds in the Oppenheimer family of funds.

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

50,000

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 in New York municipal securities that pay interest that, in the opinion of counsel to the issuer of each security, is exempt from federal and New York State and New York City personal income taxes (referred to as "New York municipal securities"). These primarily include municipal bonds, municipal notes, and interests in municipal leases. As a non-fundamental investment policy, the Fund will not invest in municipal securities the interest from which (and thus proportionate share of the exempt-interest dividends paid by the Fund) would be subject to the federal alternative minimum tax (AMT).

The Fund's New York municipal securities include tax-exempt debt obligations issued by the State of New York or its political subdivisions (cities, towns and counties, for example); agencies, public authorities and instrumentalities (these are state-chartered corporations) of the State of New York; and New York municipal securities also include U.S. territories, commonwealths and possessions (for example, Puerto Rico, Guam and the Virgin Islands) that pay interest that is exempt (in the opinion of the issuer's legal counsel when the security is issued) from federal income tax and New York State and New York City personal income taxes.

Most of the securities the Fund buys are "investment-grade," although it can invest as much as 25% of its total assets in below-investment-grade securities (commonly called "junk bonds"). 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 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 Sub-Adviser's credit analysis process is consistent with or comparable with the credit analysis process used by a nationally recognized statistical rating organization.

The Fund does not limit its investments to securities of a particular maturity range, but it generally focuses on longer-term securities to seek higher yields. The Fund can invest in inverse floaters, a variable rate obligation and form of derivative, to seek increased income and return. The Fund's investment in inverse floaters entails a degree of leverage. The Fund can expose up to 20% of its total assets to the effects of leverage from its investments in inverse floaters.

The Fund can borrow money to purchase additional securities, another form of leverage. Although the amount of borrowing will vary from time to time, the amount of leveraging from borrowings will not exceed one-third of the Fund's total assets.

In selecting investments for the Fund, the portfolio managers generally look at a wide range of New York municipal securities, including unrated bonds and securities of smaller issuers, from different issuers that provide high current tax-free income and might be overlooked by other investors and funds.

The portfolio managers may consider selling a security if any of these factors no longer applies to a security purchased for the Fund, 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.

Special Risks of Below-Investment-Grade Securities. Below-investment-grade debt securities may be subject to greater price fluctuations and have a greater risk that the issuer might not be able to pay interest and principal when due. The market for below-investment-grade securities may be less liquid and they may be harder to value or to sell at an acceptable price, especially during times of market volatility or decline.

Because the Fund can invest up to 25% of its assets in below-investment-grade securities, the Fund's credit risks are greater than those of funds that buy only investment-grade securities. This restriction is applied at the time of purchase and the Fund may continue to hold a security whose credit rating has been lowered or, in the case of an unrated security, after the Fund's adviser has changed its assessment of the security's credit quality. As a result, credit rating downgrades or other market fluctuations may cause the Fund's holdings of below-investment-grade securities to exceed this restriction for an extended period of time. If the Fund has more than 25% of its total assets invested in below-investment-grade securities, the adviser will not purchase additional below-investment-grade securities until the level of holdings in those securities no longer exceeds the restriction.

Special Risks of New York Municipal Securities. Because the Fund invests primarily in New York municipal securities, the value of its portfolio investments will be highly sensitive to events affecting the financial stability of the state of New York and its municipalities, agencies, authorities and other instrumentalities that issue those securities. Changes in legislation or policy, erosion of the tax base, the effects of terrorist acts or natural disasters, or other economic or credit problems may have a significant negative impact on the value of state or local securities.

These risks also apply to securities of issuers of U.S. territories, commonwealths or possessions located outside of New York such as Puerto Rico, Guam, the Northern Mariana Islands and the Virgin Islands.

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.

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 Concentration. While the Fund does not invest more than 25% of its total assets in a single industry, certain types of municipal securities (such as general obligation, government appropriation, municipal 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 these types of municipal securities. These types of municipal securities may finance, or pay interest from the revenues of, projects that tend to be impacted in the same way by economic, business or political developments which would increase credit risk. For example, legislation on the financing of a project or a declining economic need for the project would likely affect all similar projects.

Risks of Tobacco Related Bonds. In 1998, the largest U.S. tobacco manufacturers reached an out of court agreement, known as the Master Settlement Agreement (the "MSA"), to settle claims against them by 46 states and six other U.S. jurisdictions. The tobacco manufacturers agreed to make annual payments to the government entities in exchange for the release of all litigation claims. A number of the states have sold bonds that are backed by those future payments. The Fund may invest in two types of those bonds: (i) bonds that make payments only from a state's interest in the MSA and (ii) bonds that make payments from both the MSA revenue and from an "appropriation pledge" by the state. An "appropriation pledge" requires the state to pass a specific periodic appropriation to make the payments and is generally not an unconditional guarantee of payment by a state.

The settlement payments are based on factors, including, but not limited to, annual domestic cigarette shipments, cigarette consumption, inflation and the financial capability of participating tobacco companies. Payments could be reduced if consumption decreases, if market share is lost to non-MSA manufacturers, or if there is a negative outcome in litigation regarding the MSA, including challenges by participating tobacco manufacturers regarding the amount of annual payments owed under the MSA.

The Fund can invest up to 25% of its total assets in tobacco-related bonds without an appropriation pledge that make payments only from a state's interest in the MSA.

Main Risks of Borrowing and Leverage. The Fund can borrow up to one-third of the value of its total assets (including the amount borrowed) from banks, as permitted by the Investment Company Act of 1940. It can use those borrowings for a number of purposes, including for purchasing securities, which can create "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, for temporary and emergency purposes, or to unwind or contribute to trusts in connection with the Fund's investment in inverse floaters (instruments also involving the use of leverage, as discussed below). The Fund currently participates in a line of credit with other Oppenheimer funds for its borrowing.

Risks of Derivatives. A "derivative" is an investment whose value depends on (or is derived from) the value of an underlying security, asset, interest rate, index or currency. Derivatives may be volatile and involve significant risks. Derivative transactions may require the payment of premiums and can increase portfolio turnover. Certain derivative investments may be illiquid. The underlying security or other reference on which a derivative is based, or the derivative itself, may not perform the way the Fund expects it to. The Fund could realize little or no income or lose principal from a derivative investment or a hedge might be unsuccessful. The Fund may also lose money if the issuer of a derivative fails to pay the amount due.

Inverse Floaters. The Fund invests in inverse floating rate securities ("inverse floaters") because, under ordinary circumstances, they offer higher yields and thus provide higher income than fixed-rate municipal bonds of comparable maturity and credit quality. Because inverse floaters are leveraged instruments, the value of an inverse floater will change more significantly in response to changes in interest rates and other market fluctuations than the market value of a conventional fixed-rate municipal security of comparable maturity and credit quality, including the municipal bond underlying an inverse floater.

An inverse floater is created when a fixed-rate municipal bond is contributed to a trust. The trust issues two separate classes of securities: short-term floating rate securities with a fixed principal amount that represent a senior interest in the underlying municipal bond, and the inverse floater that represents a residual, subordinate interest in the underlying municipal bond. The trust issues and sells the short-term floating rate securities to third parties and the inverse floater to the Fund. The short-term floating rate securities generally bear short-term rates of interest. When interest is paid on the underlying municipal bond to the trust, such proceeds are first used to pay interest owing to holders of the short-term floating rate securities, with any remaining amounts being paid to the Fund, as the holder of the inverse floater. Accordingly, the amount of such interest paid to the Fund is inversely related to the rate of interest on the short-term floating rate securities. Inverse floaters produce less income when short-term interest rates rise (and, in extreme cases, may pay no income) and more income when short-term interest rates fall. Thus, if short-term interest rates rise after the issuance of the inverse floater, any yield advantage to the Fund is reduced and may be eliminated. Additionally, because the principal amount of the short-term floating rate security is fixed and is not adjusted in response to changes in the market value of the underlying municipal bond, any change in the market value of the underlying municipal bond is reflected entirely in a change to the value of the inverse floater. Upon the occurrence of certain adverse events, a trust may be collapsed and the underlying municipal bond liquidated, and the Fund could lose the entire amount of its investment in the inverse floater and may, in some cases, be contractually required to pay the negative difference, if any, between the liquidation value of the underlying municipal bond and the principal amount of the short-term floating rate securities.

The Fund may invest in inverse floaters with any degree of leverage (measured by comparing the outstanding principal amount of related short-term floating rate securities to the par value of the underlying municipal bond). However, the Fund may only expose up to 20% of its total assets to the effects of leverage from its investments in inverse floaters. This limitation is measured by comparing the aggregate principal amount of the short-term floating rate securities that are related to the inverse floaters held by the Fund to the total assets of the Fund. Nevertheless, the value of, and income earned on, an inverse floater that has a higher degree of leverage (represented by a larger outstanding principal amount of related short-term floating rate securities) will fluctuate more significantly in response to changes in interest rates and to changes in the market value of the related underlying municipal bond, and are more likely to be eliminated entirely under adverse market conditions.

Who Is the Fund Designed For? The Fund is designed for investors seeking income exempt from federal (including the alternative minimum tax), New York State and New York City personal income taxes. The Fund does not seek capital gains or growth. Investors should be willing to assume credit, interest rate and reinvestment risks. 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 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 1, 5 and 10 years compare with those of a broad measure of market performance. 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: https://www.oppenheimerfunds.com/fund/investors/overview/RochesterAMTFreeNewYorkMunicipal

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

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

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 23.97% (3rd Qtr 09) and the lowest return was -19.43% (4th Qtr 08). For the period from January 1, 2012 to December 31, 2012, the cumulative return before sales charges and taxes was 13.67%.

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® AMT-Free New York 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

5.91%

10 Years (or life of class, if less)

rr_AverageAnnualReturnYear10

5.10%

(Oppenheimer Rochester® AMT-Free New York Municipal Fund) | Barclays Capital Municipal Bond Index (reflects no deduction for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

5 Years (or life of class, if less)

rr_AverageAnnualReturnYear05

9.54%

^[1]

(Oppenheimer Rochester® AMT-Free New York Municipal Fund) | Consumer Price Index

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

1.74%

5 Years (or life of class, if less)

rr_AverageAnnualReturnYear05

1.80%

10 Years (or life of class, if less)

rr_AverageAnnualReturnYear10

2.41%

(Oppenheimer Rochester® AMT-Free New York Municipal Fund) | Consumer Price Index (reflects no deduction for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

5 Years (or life of class, if less)

rr_AverageAnnualReturnYear05

2.20%

^[1]

(Oppenheimer Rochester® AMT-Free New York Municipal Fund) | Class A

Risk/Return:

rr_RiskReturnAbstract

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

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

4.75%

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

rr_MaximumDeferredSalesChargeOverOther

none

Management Fees

rr_ManagementFeesOverAssets

0.46%

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

rr_DistributionAndService12b1FeesOverAssets

0.24%

Interest and Related Expenses from Inverse Floaters

rr_Component1OtherExpensesOverAssets

0.14%

Interest and Fees from Borrowing

rr_Component2OtherExpensesOverAssets

0.09%

Other Expenses

rr_Component3OtherExpensesOverAssets

0.05%

Total Other Expenses

rr_OtherExpensesOverAssets

0.28%

Total Annual Fund Operating Exenses

rr_ExpensesOverAssets

0.98%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

571

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

774

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

993

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,625

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

571

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

774

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

993

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

1,625

Annual Return 2003

rr_AnnualReturn2003

6.95%

Annual Return 2004

rr_AnnualReturn2004

4.38%

Annual Return 2005

rr_AnnualReturn2005

8.08%

Annual Return 2006

rr_AnnualReturn2006

8.76%

Annual Return 2007

rr_AnnualReturn2007

(2.04%)

Annual Return 2008

rr_AnnualReturn2008

(29.02%)

Annual Return 2009

rr_AnnualReturn2009

41.44%

Annual Return 2010

rr_AnnualReturn2010

2.44%

Annual Return 2011

rr_AnnualReturn2011

13.08%

Annual Return 2012

rr_AnnualReturn2012

13.67%

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 13.67%.

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Dec. 31, 2012

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

13.67%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

highest return for a calendar quarter was 23.97% (3rd Qtr 09)

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

23.97%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

lowest return was -19.43% (4th Qtr 08)

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(19.43%)

1 Year

rr_AverageAnnualReturnYear01

8.27%

5 Years (or life of class, if less)

rr_AverageAnnualReturnYear05

4.72%

10 Years (or life of class, if less)

rr_AverageAnnualReturnYear10

4.93%

Inception Date

rr_AverageAnnualReturnInceptionDate

Aug. 16, 1984

(Oppenheimer Rochester® AMT-Free New York Municipal Fund) | Class A | Return After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

8.27%

5 Years (or life of class, if less)

rr_AverageAnnualReturnYear05

4.72%

10 Years (or life of class, if less)

rr_AverageAnnualReturnYear10

4.93%

(Oppenheimer Rochester® AMT-Free New York Municipal Fund) | Class A | Return After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

7.39%

5 Years (or life of class, if less)

rr_AverageAnnualReturnYear05

4.79%

10 Years (or life of class, if less)

rr_AverageAnnualReturnYear10

4.96%

(Oppenheimer Rochester® AMT-Free New York Municipal Fund) | Class B

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

5.00%

Management Fees

rr_ManagementFeesOverAssets

0.46%

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

rr_DistributionAndService12b1FeesOverAssets

1.00%

Interest and Related Expenses from Inverse Floaters

rr_Component1OtherExpensesOverAssets

0.14%

Interest and Fees from Borrowing

rr_Component2OtherExpensesOverAssets

0.09%

Other Expenses

rr_Component3OtherExpensesOverAssets

0.15%

Total Other Expenses

rr_OtherExpensesOverAssets

0.38%

Total Annual Fund Operating Exenses

rr_ExpensesOverAssets

1.84%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

689

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

884

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,205

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,739

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

189

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

584

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

1,005

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

1,739

1 Year

rr_AverageAnnualReturnYear01

7.62%

5 Years (or life of class, if less)

rr_AverageAnnualReturnYear05

4.50%

10 Years (or life of class, if less)

rr_AverageAnnualReturnYear10

4.95%

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 01, 1993

(Oppenheimer Rochester® AMT-Free New York 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

0.46%

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

rr_DistributionAndService12b1FeesOverAssets

1.00%

Interest and Related Expenses from Inverse Floaters

rr_Component1OtherExpensesOverAssets

0.14%

Interest and Fees from Borrowing

rr_Component2OtherExpensesOverAssets

0.09%

Other Expenses

rr_Component3OtherExpensesOverAssets

0.07%

Total Other Expenses

rr_OtherExpensesOverAssets

0.30%

Total Annual Fund Operating Exenses

rr_ExpensesOverAssets

1.76%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

280

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

559

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

962

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

2,091

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

180

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

559

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

962

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

2,091

1 Year

rr_AverageAnnualReturnYear01

11.69%

5 Years (or life of class, if less)

rr_AverageAnnualReturnYear05

4.91%

10 Years (or life of class, if less)

rr_AverageAnnualReturnYear10

4.63%

Inception Date

rr_AverageAnnualReturnInceptionDate

Aug. 29, 1995

(Oppenheimer Rochester® AMT-Free New York 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

0.46%

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

rr_DistributionAndService12b1FeesOverAssets

none

Interest and Related Expenses from Inverse Floaters

rr_Component1OtherExpensesOverAssets

0.14%

Interest and Fees from Borrowing

rr_Component2OtherExpensesOverAssets

0.09%

Other Expenses

rr_Component3OtherExpensesOverAssets

0.07%

Total Other Expenses

rr_OtherExpensesOverAssets

0.30%

Total Annual Fund Operating Exenses

rr_ExpensesOverAssets

0.76%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

78

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

244

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

424

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

946

Expense Example, No Redemption, 1 Year

rr_ExpenseExampleNoRedemptionYear01

78

Expense Example, No Redemption, 3 Years

rr_ExpenseExampleNoRedemptionYear03

244

Expense Example, No Redemption, 5 Years

rr_ExpenseExampleNoRedemptionYear05

424

Expense Example, No Redemption, 10 Years

rr_ExpenseExampleNoRedemptionYear10

946

1 Year

rr_AverageAnnualReturnYear01

13.91%

5 Years (or life of class, if less)

rr_AverageAnnualReturnYear05

16.05%

10 Years (or life of class, if less)

rr_AverageAnnualReturnYear10

none

Inception Date

rr_AverageAnnualReturnInceptionDate

Jan. 31, 2011

[1] As of 1/31/2011

XML

Average Annual Total Returns (dei_DocumentInformationDocumentAxis, (Oppenheimer Rochester® AMT-Free New York Municipal Fund))	0 Months Ended
	Jan. 28, 2013
Barclays Capital Municipal Bond Index
Average Annual Return:
1 Year	6.78%
5 Years (or life of class, if less)	5.91%
10 Years (or life of class, if less)	5.10%
Barclays Capital Municipal Bond Index (reflects no deduction for fees, expenses or taxes)
Average Annual Return:
5 Years (or life of class, if less)	9.54%	[1]
Consumer Price Index
Average Annual Return:
1 Year	1.74%
5 Years (or life of class, if less)	1.80%
10 Years (or life of class, if less)	2.41%
Consumer Price Index (reflects no deduction for fees, expenses or taxes)
Average Annual Return:
5 Years (or life of class, if less)	2.20%	[1]
Class A
Average Annual Return:
1 Year	8.27%
5 Years (or life of class, if less)	4.72%
10 Years (or life of class, if less)	4.93%
Inception Date	Aug. 16, 1984
Class A | Return After Taxes on Distributions
Average Annual Return:
1 Year	8.27%
5 Years (or life of class, if less)	4.72%
10 Years (or life of class, if less)	4.93%
Class A | Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Return:
1 Year	7.39%
5 Years (or life of class, if less)	4.79%
10 Years (or life of class, if less)	4.96%
Class B
Average Annual Return:
1 Year	7.62%
5 Years (or life of class, if less)	4.50%
10 Years (or life of class, if less)	4.95%
Inception Date	Mar. 01, 1993
Class C
Average Annual Return:
1 Year	11.69%
5 Years (or life of class, if less)	4.91%
10 Years (or life of class, if less)	4.63%
Inception Date	Aug. 29, 1995
Class Y
Average Annual Return:
1 Year	13.91%
5 Years (or life of class, if less)	16.05%
10 Years (or life of class, if less)	none
Inception Date	Jan. 31, 2011

[1] As of 1/31/2011

XML

Annual Fund Operating Expenses (dei_DocumentInformationDocumentAxis, (Oppenheimer Rochester® AMT-Free New York Municipal Fund))	0 Months Ended
	Jan. 28, 2013
Class A
Operating Expenses:
Management Fees	0.46%
Disribution and/or Service (12b-1) Fees	0.24%
Interest and Related Expenses from Inverse Floaters	0.14%
Interest and Fees from Borrowing	0.09%
Other Expenses	0.05%
Total Other Expenses	0.28%
Total Annual Fund Operating Exenses	0.98%
Class B
Operating Expenses:
Management Fees	0.46%
Disribution and/or Service (12b-1) Fees	1.00%
Interest and Related Expenses from Inverse Floaters	0.14%
Interest and Fees from Borrowing	0.09%
Other Expenses	0.15%
Total Other Expenses	0.38%
Total Annual Fund Operating Exenses	1.84%
Class C
Operating Expenses:
Management Fees	0.46%
Disribution and/or Service (12b-1) Fees	1.00%
Interest and Related Expenses from Inverse Floaters	0.14%
Interest and Fees from Borrowing	0.09%
Other Expenses	0.07%
Total Other Expenses	0.30%
Total Annual Fund Operating Exenses	1.76%
Class Y
Operating Expenses:
Management Fees	0.46%
Disribution and/or Service (12b-1) Fees	none
Interest and Related Expenses from Inverse Floaters	0.14%
Interest and Fees from Borrowing	0.09%
Other Expenses	0.07%
Total Other Expenses	0.30%
Total Annual Fund Operating Exenses	0.76%