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, 2014	$ 716,145	$ 105,563	$ 365,615	$ 353,027	$ (4,499)	$ (103,561)
Beginning balance, shares at Dec. 31, 2014		91,723,028
Net Income	27,668			27,668
Other comprehensive income (loss)	4,359				4,359
Dividends, declared (USD per share)	(12,635)			(12,635)
Treasury stock acquired	(25,383)					(25,383)
Treasury stock acquired, shares		(2,918,066)
Restricted stock	860	$ 0	286	0		574
Restricted stock, shares		134,370
Ending balance at Jun. 30, 2015	711,206	$ 105,563	365,933	368,060	(140)	(128,210)
Ending balance, shares at Jun. 30, 2015		88,960,268
Stock Issued During Period, Shares, Treasury Stock Reissued		20,936
Stock Issued During Period, Value, Treasury Stock Reissued	192		32	0		160
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	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)
Restricted stock	564	$ 0	161	0		403
Restricted stock, shares		63,348
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	88,959,315	88,949,995
Stock Issued During Period, Shares, Treasury Stock Reissued		23,148
Stock Issued During Period, Value, Treasury Stock Reissued	$ 216		$ 39	$ 0		$ 177