Note 2 - Investment Securities - Investment Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Securities available for sale, amortized cost	$ 308,635	$ 274,709
Securities available for sale, gross unrealized gains	6,408	8,830
Securities available for sale, gross unrealized losses	1,503	37
Securities available for sale, fair value	313,540	283,502
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities available for sale, amortized cost	68,008	59,997
Securities available for sale, gross unrealized gains	1,108	1,362
Securities available for sale, gross unrealized losses	96	0
Securities available for sale, fair value	69,020	61,359
Agency Collateralized Mortgage Obligations [Member]
Securities available for sale, amortized cost	14,342	20,842
Securities available for sale, gross unrealized gains	275	218
Securities available for sale, gross unrealized losses	16	30
Securities available for sale, fair value	14,601	21,030
US Government Agencies Debt Securities [Member]
Securities available for sale, amortized cost	98,034	80,359
Securities available for sale, gross unrealized gains	965	1,175
Securities available for sale, gross unrealized losses	566	3
Securities available for sale, fair value	98,433	81,531
Municipal Notes [Member]
Securities available for sale, amortized cost	128,251	113,511
Securities available for sale, gross unrealized gains	4,060	6,075
Securities available for sale, gross unrealized losses	825	4
Securities available for sale, fair value	$ 131,486	$ 119,582