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, 2015	$ 719,546	$ 105,563	$ 365,981	$ 378,081	$ (2,386)	$ (127,693)
Beginning balance, shares at Dec. 31, 2015		88,961,268
Net Income	24,480			24,480
Other comprehensive income (loss)	10,333				10,333
Dividends, declared (USD per share)	(12,451)			(12,451)
Treasury stock acquired	(902)					(902)
Treasury stock acquired, shares		(97,769)
Stock Issued During Period, Value, Treasury Stock Reissued	216		39	0		177
Stock Issued During Period, Shares, Treasury Stock Reissued		23,148
Restricted stock	564	$ 0	161	0		403
Restricted stock, shares		63,348
Stock Issued During Period, Value, Treasury Stock Reissued	0
Ending balance at Jun. 30, 2016	741,786	$ 105,563	366,181	390,110	7,947	(128,015)
Ending balance, shares at Jun. 30, 2016		88,949,995
Beginning balance at Dec. 31, 2016	$ 749,929	$ 105,563	366,426	412,764	(7,027)	(127,797)
Beginning balance, shares at Dec. 31, 2016	88,961,268	89,007,077
Net Income	$ 29,901			29,901
Other comprehensive income (loss)	2,036				2,036
Dividends, declared (USD per share)	(14,917)			(14,917)
Treasury stock acquired	(1,141)					(1,141)
Treasury stock acquired, shares		(81,696)
Stock Issued During Period, Value, Treasury Stock Reissued	2,557		1,170	0		1,387
Stock Issued During Period, Shares, Treasury Stock Reissued		181,211
Restricted stock	359	$ 0	138	0		221
Restricted stock, shares		25,028
Stock Issued During Period, Value, Treasury Stock Reissued	2,258
Conversion of Stock, Shares Issued		8,351,447
Ending balance at Jun. 30, 2017	$ 879,465	$ 113,915	470,123	$ 427,748	$ (4,991)	$ (127,330)
Ending balance, shares at Jun. 30, 2017	97,483,067	97,483,067
Stock Issued During Period, Value, Other	$ 110,741	$ 8,352	$ 102,389