Condensed Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Treasury Stock [Member]
Beginning balance at Dec. 31, 2020	$ 692,472	$ 157,784	$ 296,186	$ 306,899	$ (22,144)	$ (46,253)
Beginning balance, shares at Dec. 31, 2020		29,295,052
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	32,603	$ 0	0	32,603	0	0
Other comprehensive income, net of income tax	1,704	0	0	0	1,704	0
Cash dividends declared	(5,864)	0	0	(5,864)	0	0
Stock-based compensation	822	0	878	(56)	0	0
Stock issued under dividend reinvestment and employee stock purchase plans	609	$ 0	65	(1)	0	545
Stock issued under dividend reinvestment and employee stock purchase plans, shares		23,311
Vesting of restricted stock units	(355)	$ 0	(1,126)			771
Vesting of restricted stock unit awards, shares		42,619
Exercise of stock options	759	$ 0	17	0	0	742
Shares under option, exercised		36,286
Cancellation of performance-based restricted stock awards	0	$ 0	157	0	0	(157)
Cancellation of performance-based restricted stock awards, shares		(7,199)
Purchases of treasury stock	(295)	$ 0	0	0	0	(295)
Purchases of treasury stock, shares		(10,494)
Ending balance at Mar. 31, 2021	$ 722,455	$ 157,784	296,177	333,581	(20,440)	(44,647)
Ending balance, shares at Mar. 31, 2021		29,379,575
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared, per share	$ 0.20
Beginning balance at Dec. 31, 2021	$ 773,794	$ 157,784	299,181	375,124	(16,353)	(41,942)
Beginning balance, shares at Dec. 31, 2021		29,500,542
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	20,317	$ 0	0	20,317	0	0
Other comprehensive income, net of income tax	(15,556)	0	0	0	(15,556)	0
Cash dividends declared	(5,905)	0	0	(5,905)	0	0
Stock-based compensation	869	0	1,073	(204)	0	0
Stock issued under dividend reinvestment and employee stock purchase plans	623	$ 0	59	0	0	564
Stock issued under dividend reinvestment and employee stock purchase plans, shares		21,843
Vesting of restricted stock units	(863)	$ 0	(2,418)	0	0	1,555
Vesting of restricted stock unit awards, shares		88,259
Exercise of stock options	$ 576	$ 0	50	0	0	526
Shares under option, exercised	25,781	25,781
Ending balance at Mar. 31, 2022	$ 773,855	$ 157,784	$ 297,945	$ 389,332	$ (31,909)	$ (39,297)
Ending balance, shares at Mar. 31, 2022		29,636,425
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared, per share	$ 0.20