Condensed Parent Company Only Financial Statements - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net income	$ 88,075	$ 95,916	$ 66,593
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of deferred costs	8,921	9,021	15,794
Net cash provided by operating activities	107,209	134,076	232,664
Cash flows from investing activities:
Redemption of Astoria Capital Trust I common securities	0	0	3,866
Net cash provided by investing activities	596,433	197,948	488,662
Cash flows from financing activities:
Repayments of borrowings with original terms greater than three months	(300,000)	(150,000)	(553,866)
Cost to repurchase common stock	(6,869)	0	0
Cash payments for preferred stock issuance costs	0	0	(5,204)
Cash dividends paid to stockholders	(24,856)	(24,643)	(20,688)
Net cash used in financing activities	(646,289)	(310,789)	(720,849)
Net increase in cash and cash equivalents	57,353	21,235	477
Cash and cash equivalents at beginning of year	143,185	121,950	121,473
Cash and cash equivalents at end of year	200,538	143,185	121,950
Supplemental disclosure:
Interest paid	132,687	150,026	180,871
Astoria Financial Corporation
Cash flows from operating activities:
Net income	88,075	95,916	66,593
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed earnings of subsidiaries	(36,273)	(67,852)	(39,528)
Amortization of deferred costs	531	531	531
Increase in other assets, net of other liabilities and amounts due to subsidiaries	(1,752)	(484)	(998)
Net cash provided by operating activities	50,581	28,111	26,598
Cash flows from investing activities:
Principal payments on ESOP loans receivable	0	0	5,908
Redemption of Astoria Capital Trust I common securities	0	0	3,866
Net cash provided by investing activities	0	0	9,774
Cash flows from financing activities:
Repayments of borrowings with original terms greater than three months	0	0	(128,866)
Proceeds from issuance of common and preferred stock	6,168	8,121	135,000
Cost to repurchase common stock	(6,869)	0	0
Cash payments for preferred stock issuance costs	0	0	(5,204)
Cash dividends paid to stockholders	(24,856)	(24,643)	(20,688)
Net tax benefit excess (shortfall) from stock-based compensation	2,115	192	(800)
Net cash used in financing activities	(23,442)	(16,330)	(20,558)
Net increase in cash and cash equivalents	27,139	11,781	15,814
Cash and cash equivalents at beginning of year	75,199	63,418	47,604
Cash and cash equivalents at end of year	102,338	75,199	63,418
Supplemental disclosure:
Interest paid	$ 12,500	$ 12,500	$ 18,898