Note 5 - Loans - Age Analysis of Recorded Investment in Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Past due	$ 38,057	$ 36,823
Current	4,919,698	4,782,311
Total Loans	4,957,755	4,819,134
Multi-family Residential Portfolio Segment [Member]
Past due	7,298	4,699
Current	2,254,648	2,173,805
Total Loans	2,261,946	2,178,504
Commercial Real Estate Portfolio Segment [Member]
Past due	4,607	4,533
Current	1,264,163	1,241,599
Total Loans	1,268,770	1,246,132
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member]
Past due	9,483	9,844
Current	551,872	548,658
Total Loans	561,355	558,502
One-To-Four Family - Residential Portfolio Segment [Member]
Past due	10,385	12,072
Current	173,816	173,695
Total Loans	184,201	185,767
Co-Operative Apartments Portfolio Segment [Member]
Past due	0	0
Current	7,216	7,418
Total Loans	7,216	7,418
Construction Portfolio Segment [Member]
Past due	602	0
Current	11,811	11,495
Total Loans	12,413	11,495
Small Business Administration Portfolio Segment [Member]
Past due		1,827
Current	10,519	13,371
Total Loans	10,519	15,198
Taxi Medallion Portfolio Segment [Member]
Past due	4,930	3,825
Current	13,902	15,171
Total Loans	18,832	18,996
Commercial Business and Other [Member]
Past due	752
Current	631,751
Total Loans	632,503
Commercial Business and Other Portfolio Segment [Member]
Past due		23
Current		597,099
Total Loans	632,503	597,122
Financing Receivables, 30 to 59 Days Past Due [Member]
Past due	15,737	14,475
Financing Receivables, 30 to 59 Days Past Due [Member] | Multi-family Residential Portfolio Segment [Member]
Past due	5,465	2,575
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Past due	2,194	3,363
Financing Receivables, 30 to 59 Days Past Due [Member] | One-To-Four Family - Mixed-Use Property Portfolio Segment [Member]
Past due	5,519	4,671
Financing Receivables, 30 to 59 Days Past Due [Member] | One-To-Four Family - Residential Portfolio Segment [Member]
Past due	1,379	3,831
Financing Receivables, 30 to 59 Days Past Due [Member] | Co-Operative Apartments Portfolio Segment [Member]
Past due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Construction Portfolio Segment [Member]
Past due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Small Business Administration Portfolio Segment [Member]
Past due		13
Financing Receivables, 30 to 59 Days Past Due [Member] | Taxi Medallion Portfolio Segment [Member]
Past due	1,159	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Business and Other [Member]
Past due	21
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Business and Other Portfolio Segment [Member]
Past due		22
Financing Receivables, 60 to 89 Days Past Due [Member]
Past due	4,072	1,266
Financing Receivables, 60 to 89 Days Past Due [Member] | Multi-family Residential Portfolio Segment [Member]
Past due	479	287
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Past due	876	22
Financing Receivables, 60 to 89 Days Past Due [Member] | One-To-Four Family - Mixed-Use Property Portfolio Segment [Member]
Past due	636	762
Financing Receivables, 60 to 89 Days Past Due [Member] | One-To-Four Family - Residential Portfolio Segment [Member]
Past due	1,350	194
Financing Receivables, 60 to 89 Days Past Due [Member] | Co-Operative Apartments Portfolio Segment [Member]
Past due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Construction Portfolio Segment [Member]
Past due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Small Business Administration Portfolio Segment [Member]
Past due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Taxi Medallion Portfolio Segment [Member]
Past due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Business and Other [Member]
Past due	731
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Business and Other Portfolio Segment [Member]
Past due		1
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	18,247	21,082
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Multi-family Residential Portfolio Segment [Member]
Past due	1,354	1,837
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Past due	1,537	1,148
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | One-To-Four Family - Mixed-Use Property Portfolio Segment [Member]
Past due	3,328	4,411
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | One-To-Four Family - Residential Portfolio Segment [Member]
Past due	7,655	8,047
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Co-Operative Apartments Portfolio Segment [Member]
Past due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Construction Portfolio Segment [Member]
Past due	602	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Small Business Administration Portfolio Segment [Member]
Past due		1,814
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Taxi Medallion Portfolio Segment [Member]
Past due	3,771	3,825
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Business and Other [Member]
Past due	$ 0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Business and Other Portfolio Segment [Member]
Past due