Note 4 - Loans Receivable - Loans Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Loans receivable	$ 1,073,536		$ 1,174,728
Net deferred loan origination costs	(367)		(912)
Allowance for loan losses	(8,011)	$ (8,156)	(7,632)	$ (7,603)	$ (7,824)	$ (8,470)
Loans, net	1,065,892		1,168,008
Commercial Portfolio Segment [Member]
Loans receivable	379,638		418,343
Allowance for loan losses	(1,480)	(1,658)	(2,065)	(2,040)	(2,044)	(2,272)
Consumer Portfolio Segment [Member]
Loans receivable	1,784		2,211
Allowance for loan losses	(48)	(46)	(40)	(36)	(31)	(28)
One-to-Four Family Residential Real Estate [Member] \| Real Estate Portfolio [Member]
Loans receivable	44,812		55,750
Allowance for loan losses	(623)	(665)	(675)	(580)	(563)	(699)
Multi-family Mortgage [Member] \| Real Estate Portfolio [Member]
Loans receivable	522,825		563,750
Allowance for loan losses	(4,143)	(4,185)	(3,676)	(3,728)	(3,988)	(3,991)
Nonresidential Real Estate [Member] \| Real Estate Portfolio [Member]
Loans receivable	124,477		134,674
Allowance for loan losses	$ (1,717)	$ (1,602)	$ (1,176)	$ (1,217)	$ (1,195)	$ (1,476)

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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