UNAUDITED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Dec. 31, 2013	$ 26,759	$ 204,962	$ 2,594	$ 234,315
Balance (in shares) at Dec. 31, 2013	24,040
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 0	33,883	0	33,883
Other comprehensive loss, net of tax	0	0	(1,472)	(1,472)
Dividends declared ($0.47 per share)	0	(11,333)	0	(11,333)
Dividends reinvested in common stock	$ 572	0	0	572
Dividends reinvested in common stock (in shares)	19
Stock based compensation	$ 2,624	0	0	2,624
Stock options exercised	$ 1,141	0	0	1,141
Stock options exercised (in shares)	51
Common stock issued for share awards	$ 0	0	0	0
Common stock issued for share awards (in shares)	81
Common stock issued	$ 6	0	0	6
Common stock issued (in shares)	1
Common stock repurchased	$ (1,785)	0	0	(1,785)
Common stock repurchased (in shares)	(60)
Net excess tax benefit from stock options exercised	$ 395	0	0	395
Balance at Dec. 31, 2014	$ 29,712	227,512	1,122	258,346
Balance (in shares) at Dec. 31, 2014	24,132
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 0	28,756	0	28,756
Other comprehensive loss, net of tax	0	0	(1,560)	(1,560)
Stock based compensation	2,217	0	0	2,217
Stock options exercised	$ 818	0	0	818
Stock options exercised (in shares)	35
Common stock issued for share awards	$ 0	0	0	0
Common stock issued for share awards (in shares)	105
Common stock issued	$ 8	0	0	8
Common stock issued (in shares)	2
Common stock repurchased	$ (1,799)	0	0	(1,799)
Common stock repurchased (in shares)	(54)
Net excess tax benefit from stock options exercised	$ 655	0	0	655
Balance at Sep. 30, 2015	$ 31,611	$ 256,268	$ (438)	$ 287,441
Balance (in shares) at Sep. 30, 2015	24,220