Note 2 - INVESTMENT SECURITIES - Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Securities held to maturity:
Securities held to maturity, due in one year or less, amortized cost	$ 3,666
Securities held to maturity, due in one year or less, fair value	3,672
Securities held to maturity, due after one year through five years, amortized cost	20,506
Securities held to maturity, due after one year through five years, fair value	20,571
Securities held to maturity, due after five years, amortized cost	452,651
Securities held to maturity, due after five years, fair value	460,134
Securities held to maturity, amortized cost	476,823
Securities held to maturity, fair value	484,377	$ 522,297
Securities available for sale:
Securities available for sale, due in one year or less, amortized cost	5,259
Securities available for sale, Due in one year or less, fair value	5,282
Securities available for sale, due after one year through five years, amortized cost	5,809
Securities available for sale, Due after one year through five years, fair value	5,878
Securities available for sale, due after five years, amortized cost	245,158
Securities available for sale, due after five years, fair value	225,914
Securities available for sale, single maturity, amortized cost	256,226
Securities available for sale, single maturity, fair value	237,074
Securities available for sale, amortized cost	368,020	329,994
Securities available for sale, fair value	346,686	337,830
Securities available for sale, callable, amortized cost	368,020
Securities available for sale, callable, fair value	346,686
Callable Securities [Member]
Securities available for sale:
Securities available for sale, amortized cost	229,495
Securities available for sale, fair value	211,561
Municipal securities.
Securities held to maturity:
Securities held to maturity, fair value	483,327	521,248
Securities available for sale:
Securities available for sale, amortized cost	209,052	163,253
Securities available for sale, fair value	191,473	168,266
Municipal securities. | Callable Securities [Member]
Securities held to maturity:
Securities held to maturity, callable, amortized cost	281,122
Securities held to maturity, callable, fair value	281,819
Securities available for sale:
Securities available for sale, callable, amortized cost	204,976
Securities available for sale, callable, fair value	187,341
Asset-backed securities
Securities available for sale:
Securities available for sale, amortized cost	22,859	26,372
Securities available for sale, fair value	23,232	27,124
Securities available for sale, callable, amortized cost	22,859
Securities available for sale, callable, fair value	23,232
Residential mortgage-backed and related securities
Securities available for sale:
Securities available for sale, amortized cost	88,935	92,431
Securities available for sale, fair value	86,380	94,323
Securities available for sale, callable, amortized cost	88,935
Securities available for sale, callable, fair value	86,380
Other Securities
Securities held to maturity:
Securities held to maturity, fair value	1,050	1,049
Securities available for sale:
Securities available for sale, amortized cost	24,519	24,568
Securities available for sale, fair value	24,221	$ 24,789
Other Securities | Callable Securities [Member]
Securities available for sale:
Securities available for sale, callable, amortized cost	24,519
Securities available for sale, callable, fair value	$ 24,220