Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss)
Beginning Balance (shares) at Dec. 31, 2017			49,321,231
Beginning Balance at Dec. 31, 2017	$ 1,514,983		$ 249,951	$ (19,906)	$ 898,095	$ 397,354		$ (10,511)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	146,920					146,920
Other comprehensive income (loss)	(7,385)							(7,385)
Comprehensive income	139,535
Repurchase of shares in connection with stock repurchase program (in shares)			(199,065)
Repurchase of shares in connection with stock repurchase program	(7,062)			(7,062)
Cash dividends	(43,614)					(43,614)
Common stock issued in connection with an acquisition (in shares)			9,306,477
Common stock issued in connection with an acquisition	434,519		$ 46,532		387,987
Repurchase of shares in connection with acquisition related to stock-based compensation awards (in shares)			(2,000)
Repurchase of shares in connection with acquisition related to stock-based compensation awards	(93)			(93)
Issuance of common stock for stock-based compensation awards (in shares)			119,837
Issuance of common stock for stock-based compensation awards	(1,863)			2,816	(4,679)
Stock-based compensation expense	7,251				7,251
Other, net	257				257
Ending Balance (shares) at Dec. 31, 2018			58,546,480
Ending Balance at Dec. 31, 2018	2,043,913		$ 296,483	(24,245)	1,288,911	500,660		(17,896)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	167,596					167,596
Other comprehensive income (loss)	18,660							18,660
Comprehensive income	186,256
Repurchase of shares in connection with stock repurchase program (in shares)			(1,820,202)
Repurchase of shares in connection with stock repurchase program	(62,944)			(62,944)
Cash dividends	(50,901)					(50,901)
Issuance of common stock for stock-based compensation awards (in shares)			128,724
Issuance of common stock for stock-based compensation awards	(831)			4,000	(4,831)
Stock-based compensation expense	10,196				10,196
Ending Balance (shares) at Dec. 31, 2019			56,855,002
Ending Balance at Dec. 31, 2019	$ 2,125,689	$ (35,099)	$ 296,483	(83,189)	1,294,276	617,355	$ (35,099)	764
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Net income	$ 83,651					83,651
Other comprehensive income (loss)	24,304							24,304
Comprehensive income	107,955
Repurchase of shares in connection with stock repurchase program (in shares)			(818,886)
Repurchase of shares in connection with stock repurchase program	(24,569)			(24,569)
Cash dividends	(50,134)					(50,134)
Issuance of common stock for stock-based compensation awards (in shares)			164,371
Issuance of common stock for stock-based compensation awards	(1,686)			6,204	(7,890)
Stock-based compensation expense	10,577				10,577
Ending Balance (shares) at Dec. 31, 2020			56,200,487
Ending Balance at Dec. 31, 2020	$ 2,132,733		$ 296,483	$ (101,554)	$ 1,296,963	$ 615,773		$ 25,068