Note 3 - INVESTMENT SECURITIES - Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Securities held to maturity:
Securities held to maturity, due in one year or less, amortized cost	$ 2,968
Securities held to maturity, due in one year or less, fair value	2,974
Securities held to maturity, due after one year through five years, amortized cost	16,632
Securities held to maturity, due after one year through five years, fair value	16,589
Securities held to maturity, due after five years, amortized cost	489,103
Securities held to maturity, due after five years, fair value	478,391
Securities held to maturity, amortized cost	508,703
Securities held to maturity, fair value	497,954	$ 522,297
Securities available for sale:
Securities available for sale, due in one year or less, amortized cost	6,773
Securities available for sale, Due in one year or less, fair value	6,772
Securities available for sale, due after one year through five years, amortized cost	4,129
Securities available for sale, Due after one year through five years, fair value	4,162
Securities available for sale, due after five years, amortized cost	300,364
Securities available for sale, due after five years, fair value	259,276
Securities available for sale, single maturity, amortized cost	311,266
Securities available for sale, single maturity, fair value	270,210
Securities available for sale, amortized cost	417,322	329,994
Securities available for sale, fair value	371,413	337,830
Securities available for sale, callable, amortized cost	417,322
Securities available for sale, callable, fair value	371,413
Callable Securities [Member]
Securities available for sale:
Securities available for sale, amortized cost	282,975
Securities available for sale, fair value	243,920
Municipal securities.
Securities held to maturity:
Securities held to maturity, fair value	496,904	521,248
Securities available for sale:
Securities available for sale, amortized cost	241,074	163,253
Securities available for sale, fair value	202,985	168,266
Municipal securities. | Callable Securities [Member]
Securities held to maturity:
Securities held to maturity, callable, amortized cost	309,349
Securities held to maturity, callable, fair value	305,321
Securities available for sale:
Securities available for sale, callable, amortized cost	236,628
Securities available for sale, callable, fair value	198,515
Asset-backed securities
Securities available for sale:
Securities available for sale, amortized cost	20,056	26,372
Securities available for sale, fair value	19,956	27,124
Securities available for sale, callable, amortized cost	20,056
Securities available for sale, callable, fair value	19,956
Residential mortgage-backed and related securities
Securities available for sale:
Securities available for sale, amortized cost	86,000	92,431
Securities available for sale, fair value	81,247	94,323
Securities available for sale, callable, amortized cost	86,000
Securities available for sale, callable, fair value	81,247
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	47,768	24,568
Securities available for sale, fair value	46,777	$ 24,789
Other Securities | Callable Securities [Member]
Securities available for sale:
Securities available for sale, callable, amortized cost	46,347
Securities available for sale, callable, fair value	$ 45,405