Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning balance at Dec. 31, 2012	$ 537,422	$ 77,993	$ 77,458	$ 436,039	$ (13,582)	$ (40,486)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	50,539			50,539
Other comprehensive income (loss), net of tax	888				888
Cash dividends declared	(18,137)			(18,137)
Treasury stock issued	(88)			(283)		195
Recognition of restricted stock compensation expense	586		586
Tax expense from stock-based compensation	96		96
Ending balance at Dec. 31, 2013	571,306	77,993	78,140	468,158	(12,694)	(40,291)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	57,910			57,910
Other comprehensive income (loss), net of tax	(1,139)				(1,139)
Cash dividends declared	(20,203)			(20,203)
Treasury stock issued	(163)			(1,805)		1,642
Recognition of restricted stock compensation expense	933		933
Tax expense from stock-based compensation	16		16
Issuance costs	(271)		(271)
Ending balance at Dec. 31, 2014	608,389	77,993	78,818	504,060	(13,833)	(38,649)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	67,081			67,081
Other comprehensive income (loss), net of tax	(2,624)				(2,624)
Cash dividends declared	(24,487)			(24,487)
Common stock issued in acquisition	142,469	12,333	130,136
Treasury stock issued	(182)			(2,426)		2,244
Recognition of restricted stock compensation expense	1,670		1,670
Tax expense from stock-based compensation	53		53
Issuance costs	(132)		(132)
Ending balance at Dec. 31, 2015	$ 792,237	$ 90,326	$ 210,545	$ 544,228	$ (16,457)	$ (36,405)