Condensed Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Previously Reported [Member]	Common Stock [Member]	Common Stock [Member] Previously Reported [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] Previously Reported [Member]	Retained Earnings [Member]	Retained Earnings [Member] Previously Reported [Member]	Accumulated Other Comprehensive Income (Loss), net [Member]	Accumulated Other Comprehensive Income (Loss), net [Member] Previously Reported [Member]	Treasury Stock [Member]	Treasury Stock [Member] Previously Reported [Member]
Beginning balance at Dec. 31, 2018	$ 975,389		$ 113,915		$ 492,273		$ 511,409		$ (11,341)		$ (130,867)
Beginning balance, shares at Dec. 31, 2018			98,518,668
Net Income	78,513						78,513
Other comprehensive income (loss)	17,418								17,418
Dividends, declared (USD per share)	(29,562)						(29,562)
Treasury stock acquired	(6,200)										(6,200)
Treasury stock acquired, shares			(482,608)
Stock Issued During Period, Value, Treasury Stock Reissued	2,743				1,014		0				1,729
Stock Issued During Period, Shares, Treasury Stock Reissued			205,021
Restricted stock	729		$ 0		450		0				279
Restricted stock, shares			78,000
Stock Issued During Period, Value, Treasury Stock Reissued	2,531
Ending balance at Sep. 30, 2019	1,039,030		$ 113,915		493,737		560,360		6,077		(135,059)
Ending balance, shares at Sep. 30, 2019			98,319,081
Beginning balance at Jun. 30, 2019		$ 1,021,831		$ 113,915		$ 493,737		$ 543,566		$ 3,693		$ (133,080)
Beginning balance, shares at Jun. 30, 2019				98,499,937
Net Income	26,644						26,644
Other comprehensive income (loss)	2,384								2,384
Dividends, declared (USD per share)	(9,850)						(9,850)
Treasury stock acquired	(2,240)										(2,240)
Treasury stock acquired, shares			(180,856)
Stock Issued During Period, Value, Treasury Stock Reissued	0				0		0				0
Stock Issued During Period, Shares, Treasury Stock Reissued			0
Restricted stock	261		$ 0		0		0				261
Restricted stock, shares			0
Ending balance at Sep. 30, 2019	1,039,030		$ 113,915		493,737		560,360		6,077		(135,059)
Ending balance, shares at Sep. 30, 2019			98,319,081
Beginning balance at Dec. 31, 2019	$ 1,055,665		$ 113,915		493,737		577,348		5,579		(134,914)
Beginning balance, shares at Dec. 31, 2019	98,518,668		98,311,840
Net Income	$ 47,764						47,764
Other comprehensive income (loss)	13,532								13,532
Dividends, declared (USD per share)	(32,408)						(32,408)
Treasury stock acquired	(14,373)										(14,373)
Treasury stock acquired, shares			(1,638,812)
Stock Issued During Period, Value, Treasury Stock Reissued	1,816				458		0				1,358
Stock Issued During Period, Shares, Treasury Stock Reissued			158,453
Restricted stock	835		$ 0		487		0				348
Restricted stock, shares			93,300
Stock Issued During Period, Value, Treasury Stock Reissued	1,594
Ending balance at Sep. 30, 2020	$ 1,072,831		$ 113,915		494,682		592,704		19,111		(147,581)
Ending balance, shares at Sep. 30, 2020	96,924,781		96,924,781
Beginning balance at Jun. 30, 2020	$ 1,075,705		$ 113,915		494,682		584,312		21,522		(138,726)
Beginning balance, shares at Jun. 30, 2020			98,132,697
Net Income	19,186						19,186
Other comprehensive income (loss)	(2,411)								(2,411)
Dividends, declared (USD per share)	(10,794)						(10,794)
Treasury stock acquired	(9,153)										(9,153)
Treasury stock acquired, shares			(1,207,916)
Stock Issued During Period, Value, Treasury Stock Reissued	0				0		0				0
Stock Issued During Period, Shares, Treasury Stock Reissued			0
Restricted stock	298		$ 0		0		0				298
Restricted stock, shares			0
Ending balance at Sep. 30, 2020	$ 1,072,831		$ 113,915		$ 494,682		$ 592,704		$ 19,111		$ (147,581)
Ending balance, shares at Sep. 30, 2020	96,924,781		96,924,781