Note 5 - Loans Evaluated for Impairment (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Multi-family Residential Portfolio Segment [Member]
Ending Balance	$ 2,159,138	$ 2,055,228
Ending balance: individually evaluated for impairment	8,015	8,047
Ending balance: collectively evaluated for impairment	2,151,123	2,047,181
Ending balance: individually evaluated for impairment	242	252
Ending balance: collectively evaluated for impairment	5,935	6,466
Commercial Real Estate Portfolio Segment [Member]
Ending Balance	1,146,400	1,001,236
Ending balance: individually evaluated for impairment	7,038	6,183
Ending balance: collectively evaluated for impairment	1,139,362	995,053
Ending balance: individually evaluated for impairment	201	180
Ending balance: collectively evaluated for impairment	4,244	4,059
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member]
Ending Balance	566,702	573,043
Ending balance: individually evaluated for impairment	11,605	12,828
Ending balance: collectively evaluated for impairment	555,097	560,215
Ending balance: individually evaluated for impairment	480	502
Ending balance: collectively evaluated for impairment	2,846	3,725
One-To-Four Family - Residential Portfolio Segment [Member]
Ending Balance	190,251	187,838
Ending balance: individually evaluated for impairment	10,769	12,598
Ending balance: collectively evaluated for impairment	179,482	175,240
Ending balance: individually evaluated for impairment	50	51
Ending balance: collectively evaluated for impairment	994	1,176
Co-Operative Apartments Portfolio Segment [Member]
Ending Balance	7,571	8,285
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	7,571	8,285
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment
Construction Portfolio Segment [Member]
Ending Balance	9,899	7,284
Ending balance: individually evaluated for impairment	570	1,000
Ending balance: collectively evaluated for impairment	9,329	6,284
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	75	50
Small Business Administration Portfolio Segment [Member]
Ending Balance	14,718	12,194
Ending balance: individually evaluated for impairment	938	310
Ending balance: collectively evaluated for impairment	13,780	11,884
Ending balance: individually evaluated for impairment	412
Ending balance: collectively evaluated for impairment	162	262
Taxi Medallion Portflio Segment [Member]
Ending Balance	20,641	20,881
Ending balance: individually evaluated for impairment	6,364	2,118
Ending balance: collectively evaluated for impairment	14,277	18,763
Ending balance: individually evaluated for impairment	1,035	333
Ending balance: collectively evaluated for impairment	7	10
Commercial Business and Other Portfolio Segment [Member]
Ending Balance	564,084	506,622
Ending balance: individually evaluated for impairment	2,709	4,716
Ending balance: collectively evaluated for impairment	561,375	501,906
Ending balance: individually evaluated for impairment	1	112
Ending balance: collectively evaluated for impairment	4,668	4,357
Unallocated Financing Receivables [Member]
Ending Balance
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	846
Ending Balance	4,679,404	4,372,611
Ending balance: individually evaluated for impairment	48,008	47,800
Ending balance: collectively evaluated for impairment	4,631,396	4,324,811
Ending balance: individually evaluated for impairment	2,421	1,430
Ending balance: collectively evaluated for impairment	$ 19,777	$ 20,105