Condensed Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - 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]
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		98,311,840
Net Income	4,727			4,727
Other comprehensive income (loss)	11,773				11,773
Dividends, declared (USD per share)	(10,819)			(10,819)
Treasury stock acquired	(5,220)					(5,220)
Treasury stock acquired, shares		(430,896)
Stock Issued During Period, Value, Treasury Stock Reissued	1,594		444	0		1,150
Stock Issued During Period, Shares, Treasury Stock Reissued		134,452
Restricted stock	204	$ 0	0	0		204
Restricted stock, shares		0
Stock Issued During Period, Value, Treasury Stock Reissued	1,594
Ending balance at Mar. 31, 2020	$ 1,057,924	$ 113,915	494,181	571,256	17,352	(138,780)
Ending balance, shares at Mar. 31, 2020		98,015,396
Cash Dividends Declared per Common Share (in dollars per share)	$ 0.11
Beginning balance at Dec. 31, 2020	$ 1,068,617	$ 113,915	494,683	596,614	17,233	(153,828)
Beginning balance, shares at Dec. 31, 2020	96,130,751	96,130,751
Net Income	$ 39,770			39,770
Other comprehensive income (loss)	(11,035)				(11,035)
Dividends, declared (USD per share)	(10,578)			(10,578)
Treasury stock acquired	(1,643)					(1,643)
Treasury stock acquired, shares		(123,395)
Stock Issued During Period, Value, Treasury Stock Reissued	2,041		681	0		1,360
Stock Issued During Period, Shares, Treasury Stock Reissued		158,531
Restricted stock	308	$ 0	356	0		(48)
Restricted stock, shares		82,589
Stock Issued During Period, Value, Treasury Stock Reissued	2,041
Ending balance at Mar. 31, 2021	$ 1,087,480	$ 113,915	$ 495,720	$ 625,806	$ 6,198	$ (154,159)
Ending balance, shares at Mar. 31, 2021	96,248,476	96,248,476
Cash Dividends Declared per Common Share (in dollars per share)	$ 0.11