Regulatory Matters (Regulatory Capital Requirements) (Details) $ in Thousands	Mar. 31, 2016 USD ($)
Astoria Financial Corporation
Amount
Tier 1 leverage	$ 1,536,901
Common equity tier 1 risk-based	1,413,001
Tier 1 risk-based	1,536,901
Total risk-based	$ 1,632,143
Ratio
Tier 1 leverage	10.35%
Common equity tier 1 risk-based	16.48%
Tier 1 risk-based	17.93%
Total risk-based	19.04%
Amount
Tier 1 leverage	$ 593,791
Common equity tier 1 risk-based	385,796
Tier 1 risk-based	514,395
Total risk-based	$ 685,860
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	$ 439,379
Tier 1 risk-based	567,978
Total risk-based	$ 739,443
Ratio
Common equity tier 1 risk-based	5.125%
Tier 1 risk-based	6.625%
Total risk-based	8.625%
Amount
Tier 1 leverage	$ 742,238
Common equity tier 1 risk-based	557,261
Tier 1 risk-based	685,860
Total risk-based	$ 857,325
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	$ 1,676,272
Common equity tier 1 risk-based	1,676,272
Tier 1 risk-based	1,676,272
Total risk-based	$ 1,771,514
Ratio
Tier 1 leverage	11.37%
Common equity tier 1 risk-based	19.60%
Tier 1 risk-based	19.60%
Total risk-based	20.72%
Amount
Tier 1 leverage	$ 589,580
Common equity tier 1 risk-based	384,778
Tier 1 risk-based	513,037
Total risk-based	$ 684,050
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	$ 438,219
Tier 1 risk-based	566,479
Total risk-based	$ 737,491
Ratio
Common equity tier 1 risk-based	5.125%
Tier 1 risk-based	6.625%
Total risk-based	8.625%
Amount
Tier 1 leverage	$ 736,975
Common equity tier 1 risk-based	555,790
Tier 1 risk-based	684,050
Total risk-based	$ 855,062
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

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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, Ratio [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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