Note 5 - Loans - Troubled Debt Restructurings That Are Performing According to Their Restructured Terms (Details) $ in Thousands	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016	Dec. 31, 2016 USD ($)
Number of contracts	4	9	4
Performing Financial Instruments [Member]
Number of contracts		42		33
Recorded investment	$ 22,497	$ 22,497		$ 17,435
Multi-Family Residential [Member] | Performing Financial Instruments [Member]
Number of contracts		9		9
Recorded investment	2,533	$ 2,533		$ 2,572
Commercial Real Estate Loans [Member] | Performing Financial Instruments [Member]
Number of contracts		2		2
Recorded investment	2,031	$ 2,031		$ 2,062
One-To-Four Family - Mixed Used Property [Member] | Performing Financial Instruments [Member]
Number of contracts		5		5
Recorded investment	1,765	$ 1,765		$ 1,800
One-To-Four Family - Residential [Member] | Performing Financial Instruments [Member]
Number of contracts		3		3
Recorded investment	577	$ 577		$ 591
Taxi Medallion Portfolio Segment [Member] | Performing Financial Instruments [Member]
Number of contracts		21		12
Recorded investment	15,074	$ 15,074		$ 9,735
Commercial Business and Other [Member] | Performing Financial Instruments [Member]
Number of contracts		2		2
Recorded investment	$ 517	$ 517		$ 675