Note 5 - Loans - Age Analysis of Recorded Investment in Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Loans, past due	$ 30,795	$ 28,815
Loans, current	5,287,365	5,131,421
Total Loans	5,318,160	5,160,236
Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due	11,972	7,706
Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due	4,777	4,124
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	14,046	16,985
Multi-family Residential Portfolio Segment [Member]
Loans, past due	5,462	6,410
Loans, current	2,242,390	2,267,185
Total Loans	2,247,852	2,273,595
Multi-family Residential Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due	2,887	2,533
Multi-family Residential Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due	410	279
Multi-family Residential Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	2,165	3,598
Commercial Real Estate Portfolio Segment [Member]
Loans, past due	8,793	7,774
Loans, current	1,463,101	1,360,338
Total Loans	1,471,894	1,368,112
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due	4,139	1,680
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due	3,206	2,197
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	1,448	3,897
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member]
Loans, past due	4,237	4,297
Loans, current	560,237	559,909
Total Loans	564,474	564,206
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due	2,080	1,570
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due		860
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	2,157	1,867
One-To-Four Family - Residential Portfolio Segment [Member]
Loans, past due	8,136	10,224
Loans, current	179,605	170,439
Total Loans	187,741	180,663
One-To-Four Family - Residential Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due	767	1,921
One-To-Four Family - Residential Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due	400	680
One-To-Four Family - Residential Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	6,969	7,623
Co-Operative Apartments Portfolio Segment [Member]
Loans, past due	575
Loans, current	7,264	6,895
Total Loans	7,839	6,895
Co-Operative Apartments Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due
Co-Operative Apartments Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due
Co-Operative Apartments Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	575
Construction Portfolio Segment [Member]
Loans, past due	730
Loans, current	33,096	8,479
Total Loans	33,826	8,479
Construction Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due
Construction Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due
Construction Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	730
Small Business Administration Portfolio Segment [Member]
Loans, past due	1,537
Loans, current	12,868	18,479
Total Loans	14,405	18,479
Small Business Administration Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due	1,537
Small Business Administration Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due
Small Business Administration Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due
Taxi Medallion Portfolio Segment [Member]
Loans, past due		108
Loans, current	6,225	6,726
Total Loans	6,225	6,834
Taxi Medallion Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due
Taxi Medallion Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due		108
Taxi Medallion Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due
Commercial Business and Other Portfolio Segment [Member]
Loans, past due	1,325	2
Loans, current	782,579	732,971
Total Loans	783,904	732,973
Commercial Business and Other Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due	562	2
Commercial Business and Other Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due	761
Commercial Business and Other Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	$ 2