CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Retained Earnings Impact of ASC 326 Adoption	Retained Earnings	Total	Treasury Stock	Total Stockholders' Equity Impact of ASC 326 Adoption	Total Stockholders' Equity	Noncontrolling Interest	Impact of ASC 326 Adoption	Total
Balance at Dec. 31, 2019	$ 114,858		$ 475,247	$ 12,059	$ (4,153)		$ 598,011	$ 89		$ 598,100
Balance (in shares) at Dec. 31, 2019	25,444,275
Increase (Decrease) in Stockholders' Equity
Net income			17,299				17,299			17,299
Other comprehensive income (loss), net of tax				10,491			10,491			10,491
Cash dividends declared			(7,689)				(7,689)			(7,689)
Treasury shares purchased under share repurchase plan					(10,012)		(10,012)			(10,012)
Treasury shares purchased under share repurchase plan (in shares)	(289,101)
Treasury shares purchased under deferred directors' plan	$ 215				(215)		0			0
Treasury shares purchased under deferred directors' plan (in shares)	(4,449)
Treasury shares sold and distributed under deferred directors' plan	$ (119)				119		0			0
Treasury shares sold and distributed under deferred directors' plan (in shares)	5,748
Stock activity under equity compensation plans	$ (2,030)						(2,030)			(2,030)
Stock activity under equity compensation plans (in shares)	78,099
Stock based compensation expense	$ 413						413			413
Balance at Mar. 31, 2020	$ 113,337		484,857	22,550	(14,261)		606,483	89		606,572
Balance (in shares) at Mar. 31, 2020	25,234,572
Increase (Decrease) in Stockholders' Equity
Cumulative period adjustment made to retained earnings										529,005
Balance at Dec. 31, 2020	$ 114,927		529,005	27,744	(14,581)		657,095	89		657,184
Balance (in shares) at Dec. 31, 2020	25,239,748
Increase (Decrease) in Stockholders' Equity
Net income			22,983				22,983			22,983
Other comprehensive income (loss), net of tax				(12,634)			(12,634)			(12,634)
Cash dividends declared			(8,647)				(8,647)			(8,647)
Treasury shares purchased under deferred directors' plan	$ 219				(219)		0			0
Treasury shares purchased under deferred directors' plan (in shares)	(3,634)
Treasury shares sold and distributed under deferred directors' plan	$ (115)				115		0			0
Treasury shares sold and distributed under deferred directors' plan (in shares)	5,664
Stock activity under equity compensation plans	$ (1,648)						(1,648)			(1,648)
Stock activity under equity compensation plans (in shares)	49,130
Stock based compensation expense	$ 1,381						1,381			1,381
Balance at Mar. 31, 2021	$ 114,764	$ (6,951)	$ 536,390	$ 15,110	$ (14,685)	$ (6,951)	$ 651,579	$ 89	$ (6,951)	651,668
Balance (in shares) at Mar. 31, 2021	25,290,908
Increase (Decrease) in Stockholders' Equity
Cumulative period adjustment made to retained earnings										$ 536,390