Note 18 - Fair Value of Financial Instruments - Carrying Amounts and Estimated Fair Values of Selected Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Securities held-to-maturity, fair value	$ 35,408	$ 6,180
Mortgage-backed securities	516,476	668,740
Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount	0	0
Interest rate swaps	0	0
Reported Value Measurement [Member]
Cash and due from banks	35,857	42,363
Securities held-to-maturity, fair value	37,735	6,180
Mortgage-backed securities	516,476	668,740
Other securities, at fair value pursuant to fair value option	344,905	324,657
Loans	4,835,693	4,387,979
FHLB-NY stock	59,173	56,066
Total assets	5,836,189	5,486,033
Deposits	4,205,631	3,892,547
Borrowings	1,266,563	1,271,676
Financial and Nonfinancial Liabilities, Fair Value Disclosure	5,475,580	5,168,537
Reported Value Measurement [Member] | Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount	6,350	48
Interest rate swaps	3,386	4,314
Estimate of Fair Value Measurement [Member]
Cash and due from banks	35,857	42,363
Securities held-to-maturity, fair value	35,408	6,180
Mortgage-backed securities	516,476	668,740
Other securities, at fair value pursuant to fair value option	344,905	324,657
Loans	4,814,840	4,434,079
FHLB-NY stock	59,173	56,066
Total assets	5,813,009	5,532,133
Deposits	4,213,714	3,902,888
Borrowings	1,255,283	1,279,946
Financial and Nonfinancial Liabilities, Fair Value Disclosure	5,472,383	5,187,148
Estimate of Fair Value Measurement [Member] | Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount	6,350	48
Interest rate swaps	3,386	4,314
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and due from banks	35,857	42,363
Securities held-to-maturity, fair value
Mortgage-backed securities
Other securities, at fair value pursuant to fair value option
Loans
FHLB-NY stock
Total assets	35,857	42,363
Deposits	2,833,516	2,489,245
Borrowings
Financial and Nonfinancial Liabilities, Fair Value Disclosure	2,833,516	2,489,245
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount
Interest rate swaps
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and due from banks
Securities held-to-maturity, fair value
Mortgage-backed securities	516,476	668,740
Other securities, at fair value pursuant to fair value option	337,544	317,445
Loans
FHLB-NY stock	59,173	56,066
Total assets	919,543	1,042,299
Deposits	1,380,198	1,413,643
Borrowings	1,221,324	1,250,928
Financial and Nonfinancial Liabilities, Fair Value Disclosure	2,604,908	2,668,885
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount	6,350	48
Interest rate swaps	3,386	4,314
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and due from banks
Securities held-to-maturity, fair value	35,408	6,180
Mortgage-backed securities
Other securities, at fair value pursuant to fair value option	7,361	7,212
Loans	4,814,840	4,434,079
FHLB-NY stock
Total assets	4,857,609	4,447,471
Deposits
Borrowings	33,959	29,018
Financial and Nonfinancial Liabilities, Fair Value Disclosure	33,959	29,018
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount
Interest rate swaps