Consolidated Statements Of Shareholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2012	$ 275	$ 122,414	$ 5,536	$ (39)	$ (74)	$ 128,112
Balance, shares at Dec. 31, 2012	27,486,000				(14,000)
Net income			16,172			16,172
Other comprehensive income (loss)				46		46
Comprehensive income						16,218
Cash dividends paid			(2,967)			(2,967)
Equity compensation	$ 3	3,465				3,468
Equity compensation, shares	352,000
Exercise of options	$ 4	2,728			$ (1,000)	$ 1,732
Exercise of options, shares	365,000				(102,000)	365,000
Employee stock purchase plan	$ 1	474				$ 475
Employee stock purchase plan, shares	97,000					97,000
Excess tax benefit/shortfall		(87)				$ (87)
Repurchase of common stock					$ (1,523)	(1,523)
Repurchase of common stock, shares					(253,000)
Redemption and repurchase of stock to cover tax withholdings	$ (1)	(409)			$ (271)	(681)
Redemption and repurchase of stock to cover tax withholdings, shares	(56,000)				(44,000)
Balance at Dec. 31, 2013	$ 282	128,585	18,741	7	$ (2,868)	144,747
Balance, shares at Dec. 31, 2013	28,244,000				(413,000)
Net income			7,322			7,322
Other comprehensive income (loss)				(128)		(128)
Comprehensive income						7,194
Cash dividends paid			(3,295)			(3,295)
Equity compensation	$ 6	3,691				3,697
Equity compensation, shares	642,000
Exercise of options	$ 3	2,150			$ (191)	$ 1,962
Exercise of options, shares	297,000				(18,000)	297,000
Employee stock purchase plan	$ 1	712				$ 713
Employee stock purchase plan, shares	111,000					111,000
Excess tax benefit/shortfall		738				$ 738
Repurchase of common stock					$ (5,588)	$ (5,588)
Repurchase of common stock, shares					(585,000)	(585,000)
Redemption and repurchase of stock to cover tax withholdings		(649)			$ (834)	$ (1,483)
Redemption and repurchase of stock to cover tax withholdings, shares	(65,000)				(85,000)
Balance at Dec. 31, 2014	$ 292	135,227	22,768	(121)	$ (9,481)	148,685
Balance, shares at Dec. 31, 2014	29,229,000				(1,101,000)
Net income			4,005			4,005
Other comprehensive income (loss)				45		45
Comprehensive income						4,050
Cash dividends paid			(3,408)			(3,408)
Equity compensation	$ 3	5,323				5,326
Equity compensation, shares	271,000
Exercise of options	$ 2	1,837			$ (1,002)	$ 837
Exercise of options, shares	248,000				(93,000)	248,000
Employee stock purchase plan	$ 1	688				$ 689
Employee stock purchase plan, shares	78,000					78,000
Excess tax benefit/shortfall		458				$ 458
Redemption and repurchase of stock to cover tax withholdings		(645)			$ (741)	(1,386)
Redemption and repurchase of stock to cover tax withholdings, shares	(60,000)				(71,000)
Balance at Dec. 31, 2015	$ 298	$ 142,888	$ 23,365	$ (76)	$ (11,224)	$ 155,251
Balance, shares at Dec. 31, 2015	29,766,000				(1,265,000)