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 Income (Loss), net [Member]	Treasury Stock [Member]	Previously Reported [Member]	Previously Reported [Member] Common Stock [Member]	Previously Reported [Member] Additional Paid-in-Capital [Member]	Previously Reported [Member] Retained Earnings [Member]	Previously Reported [Member] Accumulated Other Comprehensive Income (Loss), net [Member]	Previously Reported [Member] Treasury Stock [Member]	Accounting Standards Update 2018-02 [Member]	Accounting Standards Update 2018-02 [Member] Common Stock [Member]	Accounting Standards Update 2018-02 [Member] Additional Paid-in-Capital [Member]	Accounting Standards Update 2018-02 [Member] Retained Earnings [Member]	Accounting Standards Update 2018-02 [Member] Accumulated Other Comprehensive Income (Loss), net [Member]	Accounting Standards Update 2018-02 [Member] Treasury Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ (1,344)												$ 0			$ 1,344	$ (1,344)
Beginning balance at Dec. 31, 2017	888,127	$ 113,915	$ 470,123	$ 437,416	$ (6,173)	$ (127,154)							$ 888,127	$ 113,915	$ 470,123	$ 438,760	$ (7,517)	$ (127,154)
Beginning balance, Shares Outstanding at Dec. 31, 2017		97,456,478												97,456,478
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	107,498			107,498
Total other comprehensive (loss) Income	(3,824)				(3,824)
Cash dividends declared	(34,849)			(34,849)
Treasury stock acquired	(26,189)					(26,189)
Treasury stock acquired		(1,920,544)
Treasury stock reissued	44,026		21,579	0		22,447
Treasury stock reissued, Shares Outstanding		2,908,234
Restricted stock, Shares Outstanding		74,500
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	600	$ 0	571	0		29
Ending balance at Dec. 31, 2018	975,389	$ 113,915	492,273	511,409	(11,341)	(130,867)
Ending balance, Shares Outstanding at Dec. 31, 2018		98,518,668
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	105,333			105,333
Total other comprehensive (loss) Income	16,920				16,920
Cash dividends declared	(39,394)			(39,394)
Treasury stock acquired	(6,259)					(6,259)
Treasury stock acquired		(486,849)
Treasury stock reissued	2,744		1,014	0		1,730
Treasury stock reissued, Shares Outstanding		205,021
Restricted stock, Shares Outstanding		75,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	932	$ 0	450	0		482
Ending balance at Dec. 31, 2019	$ 1,055,665						$ 1,055,665	$ 113,915	$ 493,737	$ 577,348	$ 5,579	$ (134,914)
Ending balance, Shares Outstanding at Dec. 31, 2019	98,311,840							98,311,840
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	$ 73,447			73,447
Total other comprehensive (loss) Income	11,654				11,654
Cash dividends declared	(42,982)			(42,982)
Treasury stock acquired	(20,905)					(20,905)
Treasury stock acquired		(2,430,842)
Treasury stock reissued	1,817		459	0		1,358
Treasury stock reissued, Shares Outstanding		158,453
Restricted stock, Shares Outstanding		91,300
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	1,120	$ 0	487	0		633
Ending balance at Dec. 31, 2020	$ 1,068,617	$ 113,915	$ 494,683	596,614	$ 17,233	$ (153,828)
Ending balance, Shares Outstanding at Dec. 31, 2020	96,130,751	96,130,751
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 11,199			$ 11,199