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	51,869						51,869
Other comprehensive income (loss)	15,034								15,034
Dividends, declared (USD per share)	(19,712)						(19,712)
Treasury stock acquired	(3,960)										(3,960)
Treasury stock acquired, shares			(301,752)
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	468		$ 0		450		0				18
Restricted stock, shares			78,000
Stock Issued During Period, Value, Treasury Stock Reissued	2,531
Ending balance at Jun. 30, 2019	1,021,831		$ 113,915		493,737		543,566		3,693		(133,080)
Ending balance, shares at Jun. 30, 2019			98,499,937
Beginning balance at Mar. 31, 2019		$ 998,019		$ 113,915		$ 493,664		$ 526,136		$ (4,102)		$ (131,594)
Beginning balance, shares at Mar. 31, 2019				98,625,806
Net Income	27,280						27,280
Other comprehensive income (loss)	7,795								7,795
Dividends, declared (USD per share)	(9,850)						(9,850)
Treasury stock acquired	(1,886)										(1,886)
Treasury stock acquired, shares			(142,190)
Stock Issued During Period, Value, Treasury Stock Reissued	212				73		0				139
Stock Issued During Period, Shares, Treasury Stock Reissued			16,321
Restricted stock	261		$ 0		0		0				261
Restricted stock, shares			0
Ending balance at Jun. 30, 2019	1,021,831		$ 113,915		493,737		543,566		3,693		(133,080)
Ending balance, shares at Jun. 30, 2019			98,499,937
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	$ 28,578						28,578
Other comprehensive income (loss)	15,943								15,943
Dividends, declared (USD per share)	(21,614)						(21,614)
Treasury stock acquired	(5,220)										(5,220)
Treasury stock acquired, shares			(430,896)
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	537		$ 0		487		0				50
Restricted stock, shares			93,300
Stock Issued During Period, Value, Treasury Stock Reissued	1,594
Ending balance at Jun. 30, 2020	$ 1,075,705		$ 113,915		494,682		584,312		21,522		(138,726)
Ending balance, shares at Jun. 30, 2020	98,132,697		98,132,697
Beginning balance at Mar. 31, 2020	$ 1,057,924		$ 113,915		494,181		571,256		17,352		(138,780)
Beginning balance, shares at Mar. 31, 2020			98,015,396
Net Income	23,851						23,851
Other comprehensive income (loss)	4,170								4,170
Dividends, declared (USD per share)	(10,795)						(10,795)
Treasury stock acquired	0										0
Treasury stock acquired, shares			0
Stock Issued During Period, Value, Treasury Stock Reissued	222				14		0				208
Stock Issued During Period, Shares, Treasury Stock Reissued			24,001
Restricted stock	333		$ 0		487		0				(154)
Restricted stock, shares			93,300
Ending balance at Jun. 30, 2020	$ 1,075,705		$ 113,915		$ 494,682		$ 584,312		$ 21,522		$ (138,726)
Ending balance, shares at Jun. 30, 2020	98,132,697		98,132,697