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]	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]	Effect of ASU Adoption [Member] Accumulated Other Comprehensive Income (Loss), net [Member]
Cumulative effect of adoption of ASU 2018-02	$ 0			$ 1,344	$ (1,344)
Beginning balance at Dec. 31, 2017	888,127	$ 113,915	$ 470,123	438,760	(7,517)	$ (127,154)	$ 888,127	$ 113,915	$ 470,123	$ 437,416	$ (6,173)	$ (127,154)
Beginning balance, shares at Dec. 31, 2017		97,456,478						97,456,478
Net Income	23,270			23,270
Other comprehensive income (loss)	(5,492)				(5,492)
Dividends, declared (USD per share)	(7,803)			(7,803)
Treasury stock acquired	(1,079)					(1,079)
Treasury stock acquired, shares		(72,307)
Stock Issued During Period, Value, Treasury Stock Reissued	2,257		1,108	0		1,149
Stock Issued During Period, Shares, Treasury Stock Reissued		149,480
Restricted stock	69	$ 0	537	0		(468)
Restricted stock, shares		69,500
Stock Issued During Period, Value, Treasury Stock Reissued	2,257
Ending balance at Mar. 31, 2018	899,349	$ 113,915	471,768	454,227	(13,009)	(127,552)
Ending balance, shares at Mar. 31, 2018		97,603,151
Cumulative effect of adoption of ASU 2018-02													$ 0
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	98,518,668
Net Income	$ 24,589			24,589
Other comprehensive income (loss)	7,239				7,239
Dividends, declared (USD per share)	(9,862)			(9,862)
Treasury stock acquired	(2,074)					(2,074)
Treasury stock acquired, shares		(159,562)
Stock Issued During Period, Value, Treasury Stock Reissued	2,531		941	0		1,590
Stock Issued During Period, Shares, Treasury Stock Reissued		188,700
Restricted stock	207	$ 0	450	0		(243)
Restricted stock, shares		78,000
Stock Issued During Period, Value, Treasury Stock Reissued	2,531
Ending balance at Mar. 31, 2019	$ 998,019	$ 113,915	$ 493,664	$ 526,136	$ (4,102)	$ (131,594)
Ending balance, shares at Mar. 31, 2019	98,625,806	98,625,806