Note 7 - Securities Available for Sale - Securities in a Continuous Unrealized Loss Position (Details) $ in Thousands	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Less Than Twelve Months # of Investments	45	43
Less Than Twelve Months Fair Value	$ 200,675	$ 218,706
Less Than Twelve Months Unrealized Losses	$ (10,805)	$ (2,609)
Twelve Months or More # of Investments	21	5
Twelve Months or More Fair Value	$ 72,399	$ 15,132
Twelve Months or More Unrealized Losses	(5,162)	(326)
Total fair value	273,074	233,838
Total temporarily impaired securities	$ (15,967)	$ (2,935)
Collateralized Mortgage-Backed Securities [Member] | Federal National Mortgage Association Certificates and Obligations (FNMA) [Member]
Less Than Twelve Months # of Investments	24	19
Less Than Twelve Months Fair Value	$ 94,362	$ 98,423
Less Than Twelve Months Unrealized Losses	$ (5,167)	$ (1,234)
Twelve Months or More # of Investments	10	2
Twelve Months or More Fair Value	$ 34,367	$ 6,810
Twelve Months or More Unrealized Losses	(2,504)	(133)
Total fair value	128,729	105,233
Total temporarily impaired securities	$ (7,671)	$ (1,367)
Collateralized Mortgage-Backed Securities [Member] | Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member]
Less Than Twelve Months # of Investments	15	17
Less Than Twelve Months Fair Value	$ 77,184	$ 85,624
Less Than Twelve Months Unrealized Losses	$ (4,769)	$ (1,038)
Twelve Months or More # of Investments	8	2
Twelve Months or More Fair Value	$ 27,878	$ 7,664
Twelve Months or More Unrealized Losses	(2,114)	(151)
Total fair value	105,062	93,288
Total temporarily impaired securities	$ (6,883)	$ (1,189)
Other Marketable Securities [Member] | US Government Agencies Debt Securities [Member]
Less Than Twelve Months # of Investments	6	7
Less Than Twelve Months Fair Value	$ 29,129	$ 34,659
Less Than Twelve Months Unrealized Losses	$ (869)	$ (337)
Twelve Months or More # of Investments	2	0
Twelve Months or More Fair Value	$ 9,594	$ 0
Twelve Months or More Unrealized Losses	(404)	0
Total fair value	38,723	34,659
Total temporarily impaired securities	$ (1,273)	$ (337)
Other Marketable Securities [Member] | Preferred Stock [Member]
Less Than Twelve Months # of Investments	0	0
Less Than Twelve Months Fair Value	$ 0	$ 0
Less Than Twelve Months Unrealized Losses	$ 0	$ 0
Twelve Months or More # of Investments	1	1
Twelve Months or More Fair Value	$ 560	$ 658
Twelve Months or More Unrealized Losses	(140)	(42)
Total fair value	560	658
Total temporarily impaired securities	$ (140)	$ (42)