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Represents the minimum notice period requirement for redemption of debt.

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The fair value, including accrued interest, as of the date of each statement of financial position presented, of securities which are owned but transferred to serve as collateral for the payment of repurchase agreements, and that are reclassified and separately reported in the statement of financial position because the transferee has the right by contract or custom to sell or re-pledge them.

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Securities Pledged as Collateral, Amortized Cost

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Value of common stock issued by unconsolidated subsidiary trusts as of the balance sheet date which is 100% owned by the reporting entity.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Gross amount of debt extinguished.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered.

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Including both current and noncurrent portions, carrying amount as of the balance sheet date of other forms of debt not elsewhere specified in the taxonomy with initial maturities beyond one year or beyond the normal operating cycle, if longer.

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For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, maximum month-end borrowings during the period.

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Borrowings - Narrative (Details) - USD ($)			3 Months Ended	12 Months Ended
Borrowings - Narrative (Details) - USD ($)	May. 10, 2013	Jun. 19, 2012	Jun. 30, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Short Term Borrowings
Prepayment charge				$ 0	$ 0	$ 4,266,000
Astoria Capital Trust I
Short Term Borrowings
Stated interest rate	9.75%
Capital securities, aggregate liquidation amount	$ 125,000,000.0
Common securities	3,900,000
Reverse repurchase agreements
Short Term Borrowings
Percentage of collateral in residential mortgage-backed securities				83.00%	83.00%
Percentage of collateral in obligations of GSEs				17.00%	17.00%
Securities pledged as collateral for repurchase agreements, amortized cost				$ 1,210,000,000	$ 1,260,000,000
Securities pledged as collateral for repurchase agreements, fair value				$ 1,200,000,000	$ 1,260,000,000
Reverse repurchase agreements \| Minimum
Short Term Borrowings
Debt instrument, term				4 years	4 years
Reverse repurchase agreements \| Maximum
Short Term Borrowings
Debt instrument, term				7 years	7 years
Senior notes \| 5.00% Senior Notes
Short Term Borrowings
Aggregate principal amount		$ 250,000,000.0
Stated interest rate		5.00%
Minimum notice requirement		30 days
Carrying amount				$ 249,200,000	$ 248,700,000
Junior subordinated debt
Short Term Borrowings
Aggregate principal amount	$ 128,900,000.0
Stated interest rate	9.75%
Prepayment price for Junior Subordinated Debentures as a percentage of aggregate principal amount	103.413%
Debt prepayment, aggregate principal amount	$ 128,900,000
Prepayment charge			$ 4,300,000
Federal funds purchased
Short Term Borrowings
Average balance during the year				$ 481,900,000	$ 377,100,000	$ 209,400,000
Weighted average interest rate				0.33%	0.30%	0.28%
Maximum amount outstanding at any month end				$ 660,000,000	$ 455,000,000	$ 335,000,000
Federal Home Loan Bank of New York
Short Term Borrowings
Borrowing capacity				506,200,000
Securities pledged as collateral, amortized cost				150,800,000
Federal Home Loan Bank of New York \| Mortgage Loans
Short Term Borrowings
Loans pledged as collateral				$ 899,900,000