Benefit Plans - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Net actuarial loss that will be recognized as components of net periodic cost in 2016	$ 2,700
Prior service cost that will be recognized as components of net periodic cost in 2016	190
Accumulated benefit obligation	252,400	$ 270,300
Unfunded plans
Benefit Plans
Projected benefit obligation, unfunded plans	14,400	15,100
Accumulated benefit obligation, unfunded plans	14,400	15,100
Pension Benefits \| Astoria Bank
Benefit Plans
Unrealized gain related to assets held	$ 210	$ 477
Pension Benefits \| Astoria Bank \| Debt securities
Benefit Plans
Maximum securities (as a percent)	50.00%
Pension Benefits \| Astoria Bank \| Equity securities
Benefit Plans
Maximum securities (as a percent)	80.00%
Pension Benefits \| Astoria Bank \| Equity securities \| Investment in any one company
Benefit Plans
Maximum securities (as a percent)	10.00%
Pension Benefits \| Astoria Bank \| Equity securities \| Investment in any one industry
Benefit Plans
Maximum securities (as a percent)	30.00%
Pension Benefits \| Astoria Bank \| Equity securities \| Funds that mirror the S&P 500
Benefit Plans
Maximum securities (as a percent)	50.00%
Pension Benefits \| Astoria Bank \| Equity securities \| International equity securities
Benefit Plans
Maximum securities (as a percent)	10.00%
Pension Benefits \| Astoria Bank \| Liquidity funds
Benefit Plans
Maximum securities (as a percent)	25.00%
Pension Benefits \| Astoria Bank \| Large cap equity securities \| Equity securities
Benefit Plans
Maximum securities (as a percent)	50.00%
Pension Benefits \| Astoria Bank \| Mid cap equity securities \| Equity securities
Benefit Plans
Maximum securities (as a percent)	20.00%
Pension Benefits \| Astoria Bank \| Small cap equity securities \| Equity securities
Benefit Plans
Maximum securities (as a percent)	20.00%
Pension Benefits \| Astoria Bank \| PRIAC Pooled Separate Accounts \| Recurring basis \| International equity securities
Benefit Plans
Equity securities percentage in total plan assets	11.00%	9.00%
Pension Benefits \| Astoria Bank \| PRIAC Pooled Separate Accounts \| Recurring basis \| Debt securities
Benefit Plans
Equity securities percentage in total plan assets	33.00%	38.00%
Pension Benefits \| Astoria Bank \| PRIAC Pooled Separate Accounts \| Large cap equity securities \| Recurring basis
Benefit Plans
Equity securities percentage in total plan assets	44.00%	41.00%
Pension Benefits \| Astoria Bank \| PRIAC Pooled Separate Accounts \| Mid cap equity securities \| Recurring basis
Benefit Plans
Equity securities percentage in total plan assets	5.00%	5.00%
Pension Benefits \| Astoria Bank \| PRIAC Pooled Separate Accounts \| Small cap equity securities \| Recurring basis
Benefit Plans
Equity securities percentage in total plan assets	7.00%	7.00%
Pension Benefits \| Astoria Bank \| Astoria Financial Corporation common stock
Benefit Plans
Maximum securities (as a percent)	15.00%
Pension Benefits \| Astoria Bank \| Astoria Financial Corporation common stock \| Maximum
Benefit Plans
Equity securities percentage in total plan assets	10.00%

Estimated net actuarial loss that will be recognized as a component of net periodic cost in the next year

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Estimated prior service cost that will be recognized as a component in net periodic cost in the next year

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Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Unrealized Gain (Loss)

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For defined benefit pension plans, the actuarial present value of benefits (whether vested or nonvested) attributed by the pension benefit formula to employee service rendered before a specified date and based on employee service and compensation (if applicable) before that date. The accumulated benefit obligation differs from the projected benefit obligation in that it includes no assumption about future compensation levels. For plans with flat-benefit or nonpay-related pension benefit formulas, the accumulated benefit obligation and the projected benefit obligation are the same.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Accumulated Benefit Obligation
-URI http://asc.fasb.org/extlink&oid=6503844

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
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-Section 50
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If aggregate disclosures are presented, the aggregate pension accumulated benefit obligation for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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If aggregate disclosures are presented, the aggregate projected benefit obligation for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

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Target allocation maximum percentage of investments of this type to total plan assets presented on a weighted average basis.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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