Regulatory Matters (Regulatory Capital Requirements) (Details) $ in Thousands	Jun. 30, 2016 USD ($)
Astoria Financial Corporation
Amount
Tier 1 leverage	$ 1,550,012
Common equity tier 1 risk-based	1,425,940
Tier 1 risk-based	1,550,012
Total risk-based	$ 1,640,591
Ratio
Tier 1 leverage	10.462%
Common equity tier 1 risk-based	16.9334%
Tier 1 risk-based	18.40678%
Total risk-based	19.48243%
Amount
Tier 1 leverage	$ 592,626
Common equity tier 1 risk-based	378,939
Tier 1 risk-based	505,252
Total risk-based	$ 673,670
Ratio
Tier 1 leverage	4.00%
Common equity tier 1 risk-based	4.50%
Tier 1 risk-based	6.00%
Total risk-based	8.00%
Amount
Common equity tier 1 risk-based	$ 431,570
Tier 1 risk-based	557,883
Total risk-based	$ 726,300
Ratio
Common equity tier 1 risk-based	5.125%
Tier 1 risk-based	6.625%
Total risk-based	8.625%
Amount
Tier 1 leverage	$ 740,782
Common equity tier 1 risk-based	547,357
Tier 1 risk-based	673,670
Total risk-based	$ 842,087
Ratio
Tier 1 leverage	5.00%
Common equity tier 1 risk-based	6.50%
Tier 1 risk-based	8.00%
Total risk-based	10.00%
Astoria Bank
Amount
Tier 1 leverage	$ 1,698,440
Common equity tier 1 risk-based	1,698,440
Tier 1 risk-based	1,698,440
Total risk-based	$ 1,789,019
Ratio
Tier 1 leverage	11.53942%
Common equity tier 1 risk-based	20.2177%
Tier 1 risk-based	20.2177%
Total risk-based	21.29592%
Amount
Tier 1 leverage	$ 588,743
Common equity tier 1 risk-based	378,034
Tier 1 risk-based	504,046
Total risk-based	$ 672,061
Ratio
Tier 1 leverage	4.00%
Common equity tier 1 risk-based	4.50%
Tier 1 risk-based	6.00%
Total risk-based	8.00%
Amount
Common equity tier 1 risk-based	$ 430,539
Tier 1 risk-based	556,550
Total risk-based	$ 724,565
Ratio
Common equity tier 1 risk-based	5.125%
Tier 1 risk-based	6.625%
Total risk-based	8.625%
Amount
Tier 1 leverage	$ 735,929
Common equity tier 1 risk-based	546,049
Tier 1 risk-based	672,061
Total risk-based	$ 840,076
Ratio
Tier 1 leverage	5.00%
Common equity tier 1 risk-based	6.50%
Tier 1 risk-based	8.00%
Total risk-based	10.00%

Capital Required for Capital Adequacy and Conservation Buffer

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Capital Required for Capital Adequacy and Conservation Buffer to Risk Weighted Assets

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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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Common Equity Tier One Risk Based Capital

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

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Common Equity Tier One Risk Based Capital Required for Capital Adequacy and Conservation Buffer to Risk Weighted Assets

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Common Equity Tier One Risk Based Capital Required for Capital Adequacy

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The minimum common equity Tier 1 Risk Based Capital ratio (common equity tier 1 capital divided by risk weighted assets) required for capital adequacy purposes in the regulatory framework for prompt corrective action.

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Compliance with Regulatory Capital Requirements under Banking Regulations, Actual Capital, Amount [Abstract]

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Compliance with Regulatory Capital Requirements under Banking Regulations, Actual Capital, Ratio [Abstract]

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Compliance with Regulatory Capital Requirements under Banking Regulations, Capital Required to be Well Capitalized, Amount [Abstract]

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Compliance with Regulatory Capital Requirements under Banking Regulations, Minimum Capital Requirement, Amount [Abstract]

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Compliance with Regulatory Capital Requirements under Banking Regulations, Minimum Capital Requirement with Conservation Buffer, Amount [Abstract]

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Compliance with Regulatory Capital Requirements under Banking Regulations, Minimum Capital Requirement with Conservation Buffer, Ratio [Abstract]

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

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Tier One Risk Based Capital Required for Capital Adequacy and Conservation Buffer to Risk Weighted Assets

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The amount of total capital as defined in the regulations.

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The minimum amount of Total Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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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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The amount of Total Capital required to be categorized as well as capitalized under the regulatory framework for prompt corrective action.

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The Total risk based capital ratio (total capital divided by risk weighted assets) required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action.

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Total Capital divided by risk weighted assets as defined in the regulations.

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Tier 1 Leverage Capital as defined in the regulations. Also called Core Capital.

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The minimum amount of Tier 1 Leverage Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The minimum amount of Tier 1 Leverage Capital for capital adequacy purposes divided by average assets as defined in the regulations.

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The amount of Tier 1 Leverage Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

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The amount of Tier 1 Leverage Capital required to be categorized as well capitalized divided by average assets as defined in the regulatory framework for prompt corrective action.

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Tier 1 Leverage Capital divided by average assets as defined in the regulations.

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Tier 1 Risk Based Capital as defined in the regulations.

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The minimum Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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

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