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			22,817			22,817
Other comprehensive income				5,631		5,631
Stock issued in acquisition of Pulaski, net of stock issuance costs	10	195,188				195,198
Issuance of treasury stock for employee stock purchase plan		(462)			668	206
Net issuance of treasury stock for restricted stock unit vesting and related tax benefit		(93)			86	(7)
Net issuance of stock options exercised, net of shares redeemed		(818)			871	53
Cash dividends common stock of $0.36 and $0.34 per share for the period of six months ended June 2017 and 2016, respectively			(9,759)			(9,759)
Stock dividend equivalents restricted stock units at $0.36 and $0.34 per share for the period of six months ended June 2017 and 2016, respectively		165	(165)
Stock-based employee compensation		792				792
Balance at Jun. 30, 2016	39	785,825	(177,372)	7,971	(28,346)	588,117
Balance at Dec. 31, 2016	39	781,716	(163,689)	36	(23,788)	594,314
Increase (decrease) in shareholders' equity
Net income			31,649			31,649
Other comprehensive income				269		269
Issuance of treasury stock for employee stock purchase plan		(361)			664	303
Net issuance of treasury stock for restricted stock unit vesting and related tax benefit		(969)			914	(55)
Net issuance of stock options exercised, net of shares redeemed		(784)			921	137
Cash dividends common stock of $0.36 and $0.34 per share for the period of six months ended June 2017 and 2016, respectively			(13,764)			(13,764)
Stock dividend equivalents restricted stock units at $0.36 and $0.34 per share for the period of six months ended June 2017 and 2016, respectively		181	(181)
Stock dividend accrued on restricted stock awards assumed with the Pulaski acquisition at $0.36 per share			(11)			(11)
Return of 28,648 equity trust shares					(860)	(860)
Stock-based employee compensation		1,133				1,133
Balance at Jun. 30, 2017	$ 39	$ 780,916	$ (145,996)	$ 305	$ (22,149)	$ 613,115