Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands		Total	Cumulative Effect, Period of Adoption, Adjustment	[2]	Common Stock	Paid-in Capital	Treasury Stock	Accumulated Other Comprehensive (Loss) Income	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	[2]	Noncontrolling Interest
Beginning Balance (in shares) at Dec. 31, 2017					24,360,049
Beginning Balance at Dec. 31, 2017		$ 528,119			$ 24,360	$ 371,486	$ (68,179)	$ (4,414)	$ 205,549			$ (683)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		63,792							63,792
Goodwill measurement period adjustment effect on noncontrolling interest		0				2						(2)
Dividends declared		(19,209)							(19,209)
Change in other comprehensive income (loss)		(3,099)						(3,099)
Stock-based compensation		2,750				2,750
Retirement of treasury stock (in shares)					(2,253)
Retirement of treasury stock		0			$ (2)	(20)	22
Net purchase of treasury stock from stock awards for statutory tax withholdings		(1,639)					(1,639)
Net purchase of treasury stock from stock award and deferred compensation plans		2				153	(151)
Common stock issued through share-based awards and options exercises	[1]	$ 113			$ 3	110
Common stock issued through share-based awards and options exercises (in shares)		64,645			184,990
Common stock issued through share-based awards and options exercises		$ 1,566			$ 184	1,382
Shares issued in acquisitions (in shares)	[1]				2,562
Purchase of treasury stock through publicly announced plans		(5,936)					(5,936)
Repurchase of warrants from U.S. Treasury		(1,755)				(1,853)			98			0
Ending Balance (in shares) at Dec. 31, 2018					24,545,348
Ending Balance at Dec. 31, 2018		564,704			$ 24,545	374,010	(75,883)	(7,513)	250,230			(685)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		59,206							59,206
Net loss attributable to noncontrolling interest		$ (10)										(10)
Accounting Standards Update [Extensible List]		us-gaap:AccountingStandardsUpdate201613Member
Dividends declared		$ (20,783)							(20,783)
Change in other comprehensive income (loss)		9,700						9,700
Stock-based compensation		3,725				3,725
Retirement of treasury stock (in shares)					(2,704)
Retirement of treasury stock		0			$ (3)	(27)	30
Net purchase of treasury stock from stock awards for statutory tax withholdings		$ (625)					(625)
Common stock issued through share-based awards and options exercises (in shares)		49,700			107,407
Common stock issued through share-based awards and options exercises		$ 1,006			$ 108	898
Net treasury stock activity for deferred compensation trusts		(172)					(172)
Purchase of treasury stock through publicly announced plans		$ (4,524)					(4,524)
Ending Balance (in shares) at Dec. 31, 2019		24,650,051			24,650,051
Ending Balance at Dec. 31, 2019		$ 612,227	$ (2,801)		$ 24,650	378,606	(81,174)	2,187	288,653	$ (2,801)		(695)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		32,573							32,573
Net loss attributable to noncontrolling interest		(75)										(75)
Dividends declared		(21,484)							(21,484)
Change in other comprehensive income (loss)		6,761						6,761
Stock-based compensation		3,044				3,044
Retirement of treasury stock (in shares)					(3,816)
Retirement of treasury stock		0			$ (4)	(41)	45
Net purchase of treasury stock from stock awards for statutory tax withholdings		$ (633)					(633)
Common stock issued through share-based awards and options exercises (in shares)		676			67,733
Common stock issued through share-based awards and options exercises		$ 112			$ 68	44
Net treasury stock activity for deferred compensation trusts		(153)					(153)
Purchase of treasury stock through publicly announced plans		$ (7,249)					(7,249)
Ending Balance (in shares) at Dec. 31, 2020		24,713,968			24,713,968
Ending Balance at Dec. 31, 2020		$ 622,322			$ 24,714	$ 381,653	$ (89,164)	$ 8,948	$ 296,941			$ (770)

[1] Shares relating to the RBPI Merger (defined in Note 3, “Business Combinations,” below) recorded in April 2018.

[2] The Corporation adopted ASU 2016-13 (Topic 326), “Measurement of Credit Losses on Financial Instruments,” on January 1, 2020. See Note 2, "Recent Accounting Pronouncements" in the accompanying Notes to the Consolidated Financial Statements in this Annual Report on Form 10-K.