Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Dec. 31, 2012	24,803,640
Balance at Dec. 31, 2012	$ 25	$ 147,032	$ 10,570	$ (928)	$ 156,699
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures	742,467
Common shares issued on exercise of options and other	$ 1	6,495			6,496
Excess tax benefit from stock option exercises		9,873			9,873
Stock-based compensation expense		3,461			3,461
Net income			35,277		35,277
Other Comprehensive Loss, net of tax
Foreign currency translation adjustment				(163)	(163)
Comprehensive income					35,114
Balance (in shares) at Dec. 31, 2013	25,546,107
Balance at Dec. 31, 2013	$ 26	166,861	45,847	(1,091)	211,643
Other Comprehensive Loss, net of tax
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures	742,467
Common shares issued on exercise of options and other	$ 1	6,495			6,496
Excess tax benefit from stock option exercises		9,873			9,873
Stock-based compensation expense		3,461			3,461
Net income			35,277		35,277
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures	292,003
Common shares issued on exercise of options and other		4,820			4,820
Excess tax benefit from stock option exercises		4,470			4,470
Stock-based compensation expense		4,809			4,809
Net income			41,635		41,635
Foreign currency translation adjustment				(1,838)	(1,838)
Comprehensive income					$ 39,797
Balance (in shares) at Dec. 31, 2014	25,838,110				25,838,110
Balance at Dec. 31, 2014	$ 26	180,960	87,482	(2,929)	$ 265,539
Other Comprehensive Loss, net of tax
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures	292,003
Common shares issued on exercise of options and other		4,820			4,820
Excess tax benefit from stock option exercises		4,470			4,470
Stock-based compensation expense		4,809			4,809
Net income			41,635		41,635
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures	362,608
Common shares issued on exercise of options and other		6,254			6,254
Excess tax benefit from stock option exercises		5,539			5,539
Stock-based compensation expense		6,082			6,082
Net income			46,514		46,514
Foreign currency translation adjustment				(2,283)	(2,283)
Comprehensive income					$ 44,231
Balance (in shares) at Dec. 31, 2015	26,200,718				26,200,718
Balance at Dec. 31, 2015	$ 26	198,835	133,996	$ (5,212)	$ 327,645
Other Comprehensive Loss, net of tax
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures	362,608
Common shares issued on exercise of options and other		6,254			6,254
Excess tax benefit from stock option exercises		5,539			5,539
Stock-based compensation expense		$ 6,082			6,082
Net income			$ 46,514		$ 46,514