Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	AOCI Attributable to Parent [Member]	Total
Balance at Dec. 31, 2017	$ 0	$ 21,382	$ 228,750	$ 180,543	$ (79,121)	$ (840)	$ 350,714
Net income	0	0	0	36,340	0	0	36,340
Other comprehensive income (loss)	0	0	0	0	0	(589)	(589)
Common dividends declared	0	0	0	(12,966)	0	0	(12,966)
Special common dividend declared -- $0.48 per share	0	0	0	(8,124)	0	0	(8,124)
Equity-based compensation expense	0	0	535	0	623	0	1,158
Common stock options exercised	0	0	(84)	0	468	0	384
Issuance of stock to 401(k) plan	0	0	138	0	214	0	352
Purchase of treasury shares	0	0	0	0	(34,412)	0	(34,412)
Reclassification of treasury stock	0	(5,375)	(106,853)	0	112,228	0	0
Balance at Dec. 31, 2018	0	16,007	122,486	195,793	0	(1,429)	332,857
Net income	0	0	0	38,802	0	0	38,802
Other comprehensive income (loss)	0	0	0	0	0	(77)	(77)
Common dividends declared	0	0	0	(15,060)	0	0	(15,060)
Equity-based compensation expense	0	44	1,437	0	0	0	1,481
Common stock options exercised	0	8	128	0	0	0	136
Issuance of stock to 401(k) plan	0	12	399	0	0	0	411
Repurchase of common shares	0	(487)	(15,875)	0	0	0	(16,362)
Highlands Bankshares, Inc. acquisition	0	2,793	83,838	0	0	0	86,631
Balance at Dec. 31, 2019	0	18,377	192,413	219,535	0	(1,506)	428,819
Net income	0	0	0	35,926	0	0	35,926
Other comprehensive income (loss)	0	0	0	0	0	(417)	(417)
Common dividends declared	0	0	0	(17,876)	0	0	(17,876)
Equity-based compensation expense	0	58	1,585	0	0	0	1,643
Issuance of stock to 401(k) plan	0	23	484	0	0	0	507
Repurchase of common shares	0	(735)	(21,137)	0	0	0	(21,872)
Balance at Dec. 31, 2020	$ 0	$ 17,723	$ 173,345	$ 237,585	$ 0	$ (1,923)	$ 426,730