Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Deferred Compensation Trust [Member]	Retained Earnings [Member]
Beginning Balance at Dec. 31, 2010	$ 206,358	$ 24	$ 202,743	$ (2,727)	$ 6,318
Beginning Balance, Shares at Dec. 31, 2010		23,850,368
Stock compensation for options and long-term incentives	1,451		1,451
Stock compensation for options and long-term incentives, Shares		2,520
Director deferred shares for annual deferral elections	344		344
Exercise of stock options, including tax benefits of $23, $146 and $1,356 for the period ending 2011, 2012 and 2013 respectively	149		149
Exercise of stock options, including tax benefits of $23, $146 and $1,356 for the period ending 2011, 2012 and 2013 respectively, Shares		15,885
Shares issued for long-term incentive awards net of shares withheld for taxes	(203)		(203)
Shares issued for long-term incentive awards net of shares withheld for taxes, Shares		37,959
Deferred tax adjustment for long-term incentive plan	(134)		(134)
Purchase of shares by Deferred Compensation Trust	(151)		(4)	(147)
Sale of shares by Deferred Compensation Trust	114		(561)	675
Net income	11,373				11,373
Ending Balance at Dec. 31, 2011	219,301	24	203,785	(2,199)	17,691
Ending Balance, Shares at Dec. 31, 2011		23,906,732
Stock compensation for options and long-term incentives	2,089		2,089
Stock compensation for options and long-term incentives, Shares		40,152
Director deferred shares for annual deferral elections	599		599
Exercise of stock options, including tax benefits of $23, $146 and $1,356 for the period ending 2011, 2012 and 2013 respectively	913		913
Exercise of stock options, including tax benefits of $23, $146 and $1,356 for the period ending 2011, 2012 and 2013 respectively, Shares		91,748
Shares issued for long-term incentive awards net of shares withheld for taxes	(288)		(288)
Shares issued for long-term incentive awards net of shares withheld for taxes, Shares		49,785
Deferred tax adjustment for long-term incentive plan	(191)		(191)
Purchase of shares by Deferred Compensation Trust	(159)			(159)
Sale of shares by Deferred Compensation Trust	207		62	145
Net income	32,048				32,048
Ending Balance at Dec. 31, 2012	254,519	24	206,969	(2,213)	49,739
Ending Balance, Shares at Dec. 31, 2012		24,088,417
Stock compensation for options and long-term incentives	2,227		2,227
Stock compensation for options and long-term incentives, Shares		16,499
Director deferred shares for annual deferral elections	674		674
3 for 2 Stock Split	(40)		(40)
3 for 2 Stock Split, Shares		(864)
Exercise of stock options, including tax benefits of $23, $146 and $1,356 for the period ending 2011, 2012 and 2013 respectively	4,173		4,173
Exercise of stock options, including tax benefits of $23, $146 and $1,356 for the period ending 2011, 2012 and 2013 respectively, Shares	295,515	263,064
Shares issued for long-term incentive awards net of shares withheld for taxes	(1,162)		(1,162)
Shares issued for long-term incentive awards net of shares withheld for taxes, Shares		111,428
Deferred tax adjustment for long-term incentive plan	774		774
Purchase of shares by Deferred Compensation Trust	(158)			(158)
Sale of shares by Deferred Compensation Trust	158		33	125
Net income	43,627				43,627
Ending Balance at Dec. 31, 2013	$ 304,792	$ 24	$ 213,648	$ (2,246)	$ 93,366
Ending Balance, Shares at Dec. 31, 2013		24,478,544