Note 5 - Loans - Troubled Debt Restructurings That Are Not Performing According to Their Restructured Terms (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019 USD ($)	Jun. 30, 2018	Dec. 31, 2018 USD ($)
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts	0	0	0	0
Nonperforming Financial Instruments [Member]
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts			6		2
Recorded investment, not performing			$ 1,565,000		$ 1,785,000
Multi-family Residential Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts			1		1
Recorded investment, not performing			$ 391,000		$ 388,000
Taxi Medallion Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts			3		0
Recorded investment, not performing			$ 766,000		$ 0
Commercial Business and Other Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts			2		1
Recorded investment, not performing			$ 408,000		$ 1,397,000