Regulatory Matters (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Astoria Financial Corporation
Amount
Tier 1 leverage	$ 1,572,750	$ 1,521,367
Common equity tier 1 risk-based	1,448,341	1,401,376
Tier 1 risk-based	1,572,750	1,521,367
Total risk-based	$ 1,659,221	$ 1,620,612
Ratio
Tier 1 leverage	10.85%	10.21%
Common equity tier 1 risk-based	17.29%	16.00%
Tier 1 risk-based	18.78%	17.37%
Total risk-based	19.81%	18.51%
Amount
Tier 1 leverage	$ 579,829	$ 596,022
Common equity tier 1 risk-based	376,857	394,092
Tier 1 risk-based	502,477	525,456
Total risk-based	$ 669,969	$ 700,608
Ratio
Tier 1 leverage	4.00%	4.00%
Common equity tier 1 risk-based	4.50%	4.50%
Tier 1 risk-based	6.00%	6.00%
Total risk-based	8.00%	8.00%
Amount
Common equity tier 1 risk-based	$ 429,199
Tier 1 risk-based	554,818
Total risk-based	$ 722,310
Ratio
Common equity tier 1 risk-based	5.125%
Tier 1 risk-based	6.625%
Total risk-based	8.625%
Amount
Tier 1 leverage	$ 724,786	$ 745,027
Common equity tier 1 risk-based	544,350	569,244
Tier 1 risk-based	669,969	700,608
Total risk-based	$ 837,461	$ 875,760
Ratio
Tier 1 leverage	5.00%	5.00%
Common equity tier 1 risk-based	6.50%	6.50%
Tier 1 risk-based	8.00%	8.00%
Total risk-based	10.00%	10.00%
Astoria Bank
Amount
Tier 1 leverage	$ 1,742,580	$ 1,670,312
Common equity tier 1 risk-based	1,742,580	1,769,557
Tier 1 risk-based	1,742,580	1,670,312
Total risk-based	$ 1,829,051	$ 1,670,312
Ratio
Tier 1 leverage	12.09%	19.12%
Common equity tier 1 risk-based	20.85%	20.25%
Tier 1 risk-based	20.85%	11.29%
Total risk-based	21.88%	19.12%
Amount
Tier 1 leverage	$ 576,660	$ 524,204
Common equity tier 1 risk-based	376,129	698,939
Tier 1 risk-based	501,505	591,787
Total risk-based	$ 668,673	$ 393,153
Ratio
Tier 1 leverage	4.00%	6.00%
Common equity tier 1 risk-based	4.50%	8.00%
Tier 1 risk-based	6.00%	4.00%
Total risk-based	8.00%	4.50%
Amount
Common equity tier 1 risk-based	$ 428,369
Tier 1 risk-based	553,745
Total risk-based	$ 720,913
Ratio
Common equity tier 1 risk-based	5.125%
Tier 1 risk-based	6.625%
Total risk-based	8.625%
Amount
Tier 1 leverage	$ 720,825	$ 698,939
Common equity tier 1 risk-based	543,297	873,674
Tier 1 risk-based	668,673	739,734
Total risk-based	$ 835,841	$ 567,888
Ratio
Tier 1 leverage	5.00%	8.00%
Common equity tier 1 risk-based	6.50%	10.00%
Tier 1 risk-based	8.00%	5.00%
Total risk-based	10.00%	6.50%

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Common Equity Tier 1 Risk Based Capital Required to be Well Capitalized

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Common Equity Tier 1 capital divided by risk weighted assets as defined by regulations.

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Tier One Risk Based Capital Required for Capital Adequacy and Conservation Buffer

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The amount of total capital as defined in the regulations.

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The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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Tier 1 Risk Based Capital as defined in the regulations.

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The Tier 1 capital ratio (Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.

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