Basis of Presentation	3 Months Ended
Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements include the accounts of Astoria Financial Corporation and its wholly-owned subsidiaries: Astoria Bank and its subsidiaries, referred to as Astoria Bank, and AF Insurance Agency, Inc. As used in this quarterly report, “we,” “us” and “our” refer to Astoria Financial Corporation and its consolidated subsidiaries. All significant inter-company accounts and transactions have been eliminated in consolidation. In our opinion, the accompanying consolidated financial statements contain all adjustments (consisting only of normal recurring adjustments) necessary for a fair presentation of our financial condition as of March 31, 2015 and December 31, 2014, our results of operations and other comprehensive income for the three months ended March 31, 2015 and 2014, changes in our stockholders’ equity for the three months ended March 31, 2015 and our cash flows for the three months ended March 31, 2015 and 2014. In preparing the consolidated financial statements, we are required to make estimates and assumptions that affect the reported amounts of assets and liabilities for the consolidated statements of financial condition as of March 31, 2015 and December 31, 2014, and amounts of revenues, expenses and other comprehensive income in the consolidated statements of income and comprehensive income for the three months ended March 31, 2015 and 2014. The results of operations and other comprehensive income for the three months ended March 31, 2015 are not necessarily indicative of the results of operations and other comprehensive income to be expected for the remainder of the year. Certain information and note disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles, or GAAP, have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission, or SEC. These consolidated financial statements should be read in conjunction with our December 31, 2014 audited consolidated financial statements and related notes included in our 2014 Annual Report on Form 10-K. Changes in New York State and New York City Income Tax Legislation New York State, or NY State, income tax reform legislation, or the 2014 NY State legislation, was enacted on March 31, 2014. While the 2014 NY State legislation generally became effective in 2015, the nature of the changes resulted in the recognition of certain deferred tax assets in the 2014 first quarter. Prior to the effective date of the 2014 NY State legislation, we were subject to taxation in NY State under an alternative taxation method based on assets. The 2014 NY State legislation, among other things, removed that alternative method. Further, the new law (1) requires that we will be taxed in a manner that resulted in an increase in our income tax expense beginning in 2015 and (2) caused us to recognize temporary differences and net operating loss carry-forward benefits in 2014 which we were unable to recognize previously. The result of the 2014 NY State legislation was an increase in our net deferred tax asset with a corresponding reduction in income tax expense of $11.5 million in the 2014 first quarter. On April 13, 2015, a package of bills, or the 2015 NY State legislation, was signed into law in NY State that, among other things, (1) conforms New York City, or NY City, banking income tax laws to the 2014 NY State legislation, and (2) makes technical corrections to the 2014 NY State legislation. The 2015 NY State legislation is effective retroactively to tax years beginning on or after January 1, 2015. Under GAAP, the effects of changes in tax law on current and deferred taxes are accounted for in the period that includes the enactment date of the change, which means that we will be adjusting to the impact of the legislation in the second quarter of 2015. We are presently reviewing the impact of the 2015 NY State legislation, and anticipate the net impact of adjusting to the legislation will result in a credit to income tax expense in the 2015 second quarter, followed most likely by a higher effective income tax rate going forward. We currently expect that the effects of the 2015 NY State legislation in the 2015 second quarter will include (i) the reduction or elimination of our valuation allowance, totaling $7.2 million at March 31, 2015, which presently offsets certain net deferred tax assets related to NY City income taxes, and (ii) the recognition of additional deferred tax assets relating to NY City income tax benefits to become realizable in future periods, which in the aggregate will more than offset (iii) additional one-time income tax expense to be recorded in the 2015 second quarter, applicable to the first quarter of 2015, as this legislative change is retroactively applicable to January 1, 2015.

Basis of Presentation

The accompanying consolidated financial statements include the accounts of Astoria Financial Corporation and its wholly-owned subsidiaries: Astoria Bank and its subsidiaries, referred to as Astoria Bank, and AF Insurance Agency, Inc. As used in this quarterly report, “we,” “us” and “our” refer to Astoria Financial Corporation and its consolidated subsidiaries. All significant inter-company accounts and transactions have been eliminated in consolidation.

In our opinion, the accompanying consolidated financial statements contain all adjustments (consisting only of normal recurring adjustments) necessary for a fair presentation of our financial condition as of March 31, 2015 and December 31, 2014, our results of operations and other comprehensive income for the three months ended March 31, 2015 and 2014, changes in our stockholders’ equity for the three months ended March 31, 2015 and our cash flows for the three months ended March 31, 2015 and 2014. In preparing the consolidated financial statements, we are required to make estimates and assumptions that affect the reported amounts of assets and liabilities for the consolidated statements of financial condition as of March 31, 2015 and December 31, 2014, and amounts of revenues, expenses and other comprehensive income in the consolidated statements of income and comprehensive income for the three months ended March 31, 2015 and 2014. The results of operations and other comprehensive income for the three months ended March 31, 2015 are not necessarily indicative of the results of operations and other comprehensive income to be expected for the remainder of the year. Certain information and note disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles, or GAAP, have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission, or SEC.

These consolidated financial statements should be read in conjunction with our December 31, 2014 audited consolidated financial statements and related notes included in our 2014 Annual Report on Form 10-K.

Changes in New York State and New York City Income Tax Legislation

New York State, or NY State, income tax reform legislation, or the 2014 NY State legislation, was enacted on March 31, 2014. While the 2014 NY State legislation generally became effective in 2015, the nature of the changes resulted in the recognition of certain deferred tax assets in the 2014 first quarter. Prior to the effective date of the 2014 NY State legislation, we were subject to taxation in NY State under an alternative taxation method based on assets. The 2014 NY State legislation, among other things, removed that alternative method. Further, the new law (1) requires that we will be taxed in a manner that resulted in an increase in our income tax expense beginning in 2015 and (2) caused us to recognize temporary differences and net operating loss carry-forward benefits in 2014 which we were unable to recognize previously. The result of the 2014 NY State legislation was an increase in our net deferred tax asset with a corresponding reduction in income tax expense of $11.5 million in the 2014 first quarter.

On April 13, 2015, a package of bills, or the 2015 NY State legislation, was signed into law in NY State that, among other things, (1) conforms New York City, or NY City, banking income tax laws to the 2014 NY State legislation, and (2) makes technical corrections to the 2014 NY State legislation. The 2015 NY State legislation is effective retroactively to tax years beginning on or after January 1, 2015. Under GAAP, the effects of changes in tax law on current and deferred taxes are accounted for in the period that includes the enactment date of the change, which means that we will be adjusting to the impact of the legislation in the second quarter of 2015. We are presently reviewing the impact of the 2015 NY State legislation, and anticipate the net impact of adjusting to the legislation will result in a credit to income tax expense in the 2015 second quarter, followed most likely by a higher effective income tax rate going forward. We currently expect that the effects of the 2015 NY State legislation in the 2015 second quarter will include (i) the reduction or elimination of our valuation allowance, totaling $7.2 million at March 31, 2015, which presently offsets certain net deferred tax assets related to NY City income taxes, and (ii) the recognition of additional deferred tax assets relating to NY City income tax benefits to become realizable in future periods, which in the aggregate will more than offset (iii) additional one-time income tax expense to be recorded in the 2015 second quarter, applicable to the first quarter of 2015, as this legislative change is retroactively applicable to January 1, 2015.