Note 5 - Loans - Loans Evaluated for Impairment (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Financing Receivables:
Financing receivables, ending balance	$ 5,318,160	$ 5,160,236
Financing receivables, individually evaluated for impairment	48,947	39,163
Financing receivables, collectively evaluated for impairment	5,269,213	5,121,073
Ending balance: individually evaluated for impairment	363	642
Ending balance: collectively evaluated for impairment	19,857	19,709
Multi-family Residential Portfolio Segment [Member]
Financing Receivables:
Financing receivables, ending balance	2,247,852	2,273,595
Financing receivables, individually evaluated for impairment	6,482	7,311
Financing receivables, collectively evaluated for impairment	2,241,370	2,266,284
Ending balance: individually evaluated for impairment	147	205
Ending balance: collectively evaluated for impairment	5,391	5,618
Commercial Real Estate Portfolio Segment [Member]
Financing Receivables:
Financing receivables, ending balance	1,471,894	1,368,112
Financing receivables, individually evaluated for impairment	4,967	9,089
Financing receivables, collectively evaluated for impairment	1,466,927	1,359,023
Ending balance: individually evaluated for impairment		177
Ending balance: collectively evaluated for impairment	4,726	4,466
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member]
Financing Receivables:
Financing receivables, ending balance	564,474	564,206
Financing receivables, individually evaluated for impairment	5,625	5,445
Financing receivables, collectively evaluated for impairment	558,849	558,761
Ending balance: individually evaluated for impairment	159	198
Ending balance: collectively evaluated for impairment	2,138	2,347
One-To-Four Family - Residential Portfolio Segment [Member]
Financing Receivables:
Financing receivables, ending balance	187,741	180,663
Financing receivables, individually evaluated for impairment	8,733	9,686
Financing receivables, collectively evaluated for impairment	179,008	170,977
Ending balance: individually evaluated for impairment	53	56
Ending balance: collectively evaluated for impairment	950	1,026
Co-Operative Apartments Portfolio Segment [Member]
Financing Receivables:
Financing receivables, ending balance	7,839	6,895
Financing receivables, individually evaluated for impairment	0	0
Financing receivables, collectively evaluated for impairment	7,839	6,895
Ending balance: individually evaluated for impairment	0	0
Ending balance: collectively evaluated for impairment	0	0
Construction Portfolio Segment [Member]
Financing Receivables:
Financing receivables, ending balance	33,826	8,479
Financing receivables, individually evaluated for impairment	730
Financing receivables, collectively evaluated for impairment	33,096	8,479
Ending balance: individually evaluated for impairment	0	0
Ending balance: collectively evaluated for impairment	264	68
Small Business Administration Portfolio Segment [Member]
Financing Receivables:
Financing receivables, ending balance	14,405	18,479
Financing receivables, individually evaluated for impairment	49	137
Financing receivables, collectively evaluated for impairment	14,356	18,342
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	549	669
Taxi Medallion Portfolio Segment [Member]
Financing Receivables:
Financing receivables, ending balance	6,225	6,834
Financing receivables, individually evaluated for impairment	6,225	6,834
Financing receivables, collectively evaluated for impairment
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment
Commercial Business and Other Portfolio Segment [Member]
Financing Receivables:
Financing receivables, ending balance	783,904	732,973
Financing receivables, individually evaluated for impairment	16,136	661
Financing receivables, collectively evaluated for impairment	767,768	732,312
Ending balance: individually evaluated for impairment	4	6
Ending balance: collectively evaluated for impairment	5,828	5,515
Unallocated Financing Receivables [Member]
Financing Receivables:
Financing receivables, ending balance
Financing receivables, individually evaluated for impairment
Financing receivables, collectively evaluated for impairment
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	$ 11

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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