Note 5 - Loans - Loans Evaluated for Impairment (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financing receivables, ending balance	$ 5,053,451	$ 4,819,134
Financing receivables, individually evaluated for impairment	48,376	51,983
Financing receivables, collectively evaluated for impairment	5,005,075	4,767,151
Ending balance: individually evaluated for impairment	6,632	3,226
Ending balance: collectively evaluated for impairment	18,637	19,003
Multi-family Residential Portfolio Segment [Member]
Financing receivables, ending balance	2,236,173	2,178,504
Financing receivables, individually evaluated for impairment	4,721	5,923
Financing receivables, collectively evaluated for impairment	2,231,452	2,172,581
Ending balance: individually evaluated for impairment	217	232
Ending balance: collectively evaluated for impairment	5,519	5,691
Commercial Real Estate Portfolio Segment [Member]
Financing receivables, ending balance	1,352,775	1,246,132
Financing receivables, individually evaluated for impairment	6,798	6,551
Financing receivables, collectively evaluated for impairment	1,345,977	1,239,581
Ending balance: individually evaluated for impairment	154	179
Ending balance: collectively evaluated for impairment	4,473	4,308
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member]
Financing receivables, ending balance	556,723	558,502
Financing receivables, individually evaluated for impairment	6,317	8,809
Financing receivables, collectively evaluated for impairment	550,406	549,693
Ending balance: individually evaluated for impairment	206	417
Ending balance: collectively evaluated for impairment	2,312	2,486
One-To-Four Family - Residential Portfolio Segment [Member]
Financing receivables, ending balance	177,578	185,767
Financing receivables, individually evaluated for impairment	10,079	9,989
Financing receivables, collectively evaluated for impairment	167,499	175,778
Ending balance: individually evaluated for impairment	56	60
Ending balance: collectively evaluated for impairment	902	955
Co-Operative Apartments Portfolio Segment [Member]
Financing receivables, ending balance	7,035	7,418
Financing receivables, individually evaluated for impairment	0	0
Financing receivables, collectively evaluated for impairment	7,035	7,418
Ending balance: individually evaluated for impairment	0	0
Ending balance: collectively evaluated for impairment	0	0
Construction Portfolio Segment [Member]
Financing receivables, ending balance	15,811	11,495
Financing receivables, individually evaluated for impairment	1,178
Financing receivables, collectively evaluated for impairment	14,633	11,495
Ending balance: individually evaluated for impairment	0	0
Ending balance: collectively evaluated for impairment	117	92
Small Business Administration Portfolio Segment [Member]
Financing receivables, ending balance	14,485	15,198
Financing receivables, individually evaluated for impairment	370	1,937
Financing receivables, collectively evaluated for impairment	14,115	13,261
Ending balance: individually evaluated for impairment		90
Ending balance: collectively evaluated for impairment	393	391
Taxi Medallion Portfolio Segment [Member]
Financing receivables, ending balance	18,165	18,996
Financing receivables, individually evaluated for impairment	18,165	16,282
Financing receivables, collectively evaluated for impairment		2,714
Ending balance: individually evaluated for impairment	5,991	2,236
Ending balance: collectively evaluated for impairment		7
Commercial Business and Other Portfolio Segment [Member]
Financing receivables, ending balance	674,706	597,122
Financing receivables, individually evaluated for impairment	748	2,492
Financing receivables, collectively evaluated for impairment	673,958	594,630
Ending balance: individually evaluated for impairment	8	12
Ending balance: collectively evaluated for impairment	$ 4,921	4,480
Unallocated Financing Receivables [Member]
Financing receivables, ending balance		0
Financing receivables, individually evaluated for impairment		0
Financing receivables, collectively evaluated for impairment		0
Ending balance: individually evaluated for impairment		0
Ending balance: collectively evaluated for impairment		$ 593

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

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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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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524

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