CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (loss)	Treasury Stock	Total
Balance at Dec. 31, 2015	$ 29	$ 591,053	$ (190,265)	$ 2,340	$ (29,971)	$ 373,186
Increase (decrease) in shareholders' equity
Net income			10,434			10,434
Other comprehensive (loss) income				3,977		3,977
Issuance of treasury stock for employee stock purchase plan		(370)			533	163
Net issuance of treasury stock for restricted stock unit vesting and related tax benefit		(78)			72	(6)
Cash dividends common stock of $0.18 and $0.17 per share for the period of three months ended March 2017 and 2016, respectively			(4,879)			(4,879)
Stock dividend equivalents restricted stock units of $0.18 and $0.17 per share for the period of three months ended March 2017 and 2016, respectively		82	(82)
Stock-based employee compensation		389				389
Balance at Mar. 31, 2016	29	591,076	(184,792)	6,317	(29,366)	383,264
Balance at Dec. 31, 2016	39	781,716	(163,689)	36	(23,788)	594,314
Increase (decrease) in shareholders' equity
Net income			15,170			15,170
Other comprehensive (loss) income				(171)		(171)
Issuance of treasury stock for employee stock purchase plan		(239)			439	200
Net issuance of treasury stock for restricted stock unit vesting and related tax benefit		(1,017)			914	(103)
Net issuance of stock options exercised, net of shares redeemed		(681)			818	137
Cash dividends common stock of $0.18 and $0.17 per share for the period of three months ended March 2017 and 2016, respectively			(6,879)			(6,879)
Stock dividend equivalents restricted stock units of $0.18 and $0.17 per share for the period of three months ended March 2017 and 2016, respectively		103	(103)
Stock dividend accrued on restricted stock awards assumed with the Pulaski acquisition at $0.18 per share			(6)			(6)
Return of 28,648 equity trust shares					(860)	(860)
Stock-based employee compensation		545				545
Balance at Mar. 31, 2017	$ 39	$ 780,427	$ (155,507)	$ (135)	$ (22,477)	$ 602,347