CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (unaudited) - USD ($) $ in Thousands	Total	Impact of ASC 326 Adoption	Total Stockholders’ Equity	Total Stockholders’ Equity Impact of ASC 326 Adoption	Common Stock	Retained Earnings	Retained Earnings Impact of ASC 326 Adoption	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Noncontrolling Interest
Balance (in shares) at Dec. 31, 2019					25,444,275
Beginning balance at Dec. 31, 2019	$ 598,100		$ 598,011		$ 114,858	$ 475,247		$ 12,059	$ (4,153)	$ 89
Increase (Decrease) in Stockholders' Equity
Net income	36,969		36,969			36,969
Other comprehensive income (loss), net of tax	12,743		12,743					12,743
Cash dividends declared and paid	(15,325)		(15,325)			(15,325)
Treasury shares purchased under share repurchase plan (in shares)					(289,101)
Treasury shares purchased under share repurchase plan	(10,012)		(10,012)		$ 0				(10,012)
Treasury shares purchased under deferred directors' plan (in shares)					(5,741)
Treasury shares purchased under deferred directors' plan	$ 0		0		$ 268				(268)
Treasury shares sold and distributed under deferred directors' plan (in shares)	5,748
Treasury shares sold and distributed under deferred directors' plan	$ 0		0		$ (119)				119
Stock activity under equity compensation plans (in shares)					78,099
Stock activity under equity compensation plans	(2,030)		(2,030)		$ (2,030)
Stock based compensation expense	447		447		$ 447
Balance (in shares) at Jun. 30, 2020					25,233,280
Ending balance at Jun. 30, 2020	620,892		620,803		$ 113,424	496,891		24,802	(14,314)	89
Balance (in shares) at Dec. 31, 2019					25,444,275
Beginning balance at Dec. 31, 2019	$ 598,100		598,011		$ 114,858	475,247		12,059	(4,153)	89
Increase (Decrease) in Stockholders' Equity
Accounting standards update	ASU 2016-13
Balance (in shares) at Dec. 31, 2020					25,239,748
Ending balance at Dec. 31, 2020	$ 657,184	$ (6,951)	657,095	$ (6,951)	$ 114,927	529,005	$ (6,951)	27,744	(14,581)	89
Balance (in shares) at Mar. 31, 2020					25,234,572
Beginning balance at Mar. 31, 2020	606,572		606,483		$ 113,337	484,857		22,550	(14,261)	89
Increase (Decrease) in Stockholders' Equity
Net income	19,670		19,670			19,670
Other comprehensive income (loss), net of tax	2,252		2,252					2,252
Cash dividends declared and paid	(7,636)		(7,636)			(7,636)
Treasury shares purchased under deferred directors' plan (in shares)					(1,292)
Treasury shares purchased under deferred directors' plan	0		0		$ 53				(53)
Stock activity under equity compensation plans	0		0
Stock based compensation expense	34		34		$ 34
Balance (in shares) at Jun. 30, 2020					25,233,280
Ending balance at Jun. 30, 2020	620,892		620,803		$ 113,424	496,891		24,802	(14,314)	89
Balance (in shares) at Dec. 31, 2020					25,239,748
Beginning balance at Dec. 31, 2020	657,184	$ (6,951)	657,095	$ (6,951)	$ 114,927	529,005	$ (6,951)	27,744	(14,581)	89
Increase (Decrease) in Stockholders' Equity
Net income	47,331		47,331			47,331
Other comprehensive income (loss), net of tax	(5,473)		(5,473)					(5,473)
Cash dividends declared and paid	(17,322)		(17,322)			(17,322)
Treasury shares purchased under deferred directors' plan (in shares)					(4,576)
Treasury shares purchased under deferred directors' plan	0		0		$ 282				(282)
Treasury shares sold and distributed under deferred directors' plan (in shares)					5,664
Treasury shares sold and distributed under deferred directors' plan	0		0		$ (115)				115
Stock activity under equity compensation plans (in shares)					49,130
Stock activity under equity compensation plans	(1,648)		(1,648)		$ (1,648)
Stock based compensation expense	4,350		4,350		$ 4,350
Balance (in shares) at Jun. 30, 2021					25,289,966
Ending balance at Jun. 30, 2021	677,471		677,382		$ 117,796	552,063		22,271	(14,748)	89
Balance (in shares) at Mar. 31, 2021					25,290,908
Beginning balance at Mar. 31, 2021	651,668		651,579		$ 114,764	536,390		15,110	(14,685)	89
Increase (Decrease) in Stockholders' Equity
Net income	24,348		24,348			24,348
Other comprehensive income (loss), net of tax	7,161		7,161					7,161
Cash dividends declared and paid	(8,675)		(8,675)			(8,675)
Treasury shares purchased under deferred directors' plan (in shares)					(942)
Treasury shares purchased under deferred directors' plan	0		0		$ 63				(63)
Treasury shares sold and distributed under deferred directors' plan	0		0
Stock activity under equity compensation plans	0		0
Stock based compensation expense	2,969		2,969		$ 2,969
Balance (in shares) at Jun. 30, 2021					25,289,966
Ending balance at Jun. 30, 2021	$ 677,471		$ 677,382		$ 117,796	$ 552,063		$ 22,271	$ (14,748)	$ 89