Note 22 - Parent Company Financial Information - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net income	$ 11,550	$ 8,266	$ 8,238	$ 7,872	$ 9,564	$ 9,156	$ 10,451	$ 9,631	$ 35,926	$ 38,802	$ 36,340
(Increase) decrease in other operating activities									(6,662)	7,003	3,974
Net cash provided by operating activities									45,844	56,655	49,499
Investing activities
Net cash provided by investing activities									17,798	171,377	49,398
Payments for repurchase of common stock									21,872	16,362	34,412
Payments of common stock dividends									(17,876)	(15,060)	(21,090)
Net cash used in financing activities									175,910	(87,896)	(179,975)
Parent Company [Member]
Net income									35,926	38,802	36,340
(Increase) decrease in other operating activities									1,047	1,865	1,509
Net cash provided by operating activities									36,973	40,667	37,849
Investing activities
Dividends in excess of undistributed net income of subsidiaries									(13,284)	(1,002)	10,268
Net cash provided by investing activities									(13,284)	(1,002)	10,268
Proceeds from issuance of common stock									0	136	832
Payments for repurchase of common stock									(21,872)	(16,362)	(34,412)
Payments of common stock dividends									(17,876)	(15,060)	(21,090)
Net change in other financing activities									2,150	1,893	1,063
Net cash used in financing activities									(37,598)	(29,393)	(53,607)
Net increase (decrease) in cash and cash equivalents									(13,909)	10,272	(5,490)
Cash and cash equivalents at beginning of period				$ 23,998				$ 13,726	23,998	13,726	19,216
Cash and cash equivalents at end of period	$ 10,089				$ 23,998				$ 10,089	$ 23,998	$ 13,726