Consolidated Statements of Stockholders' Equity (USD $) In Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]
Beginning Balance at Dec. 31, 2010	$ 127,501	$ 458	$ (782)	$ 77,449	$ (445)	$ 50,821
Beginning Balance, Shares at Dec. 31, 2010		45,811	50
Comprehensive income	50,631				85	50,546
Common stock purchased for treasury	(23,112)		(23,112)
Common stock purchased for treasury, Shares			1,607
Share-based compensation	6,452			6,452
Share-based compensation, Shares		4
Exercise of stock options	1,681	2		1,679
Exercise of stock options, Shares		140
Excess tax benefits	140			140
Ending Balance at Dec. 31, 2011	163,293	460	(23,894)	85,720	(360)	101,367
Ending Balance, Shares at Dec. 31, 2011		45,955	1,657
Comprehensive income	69,584				137	69,447
Common stock purchased for treasury	(15,242)		(15,242)
Common stock purchased for treasury, Shares			753
Share-based compensation	7,811	6		7,805
Share-based compensation, Shares		570
Restricted shares forfeited			10
Exercise of stock options	8,049	5		8,044
Exercise of stock options, Shares		611
Excess tax benefits	564			564
Ending Balance at Dec. 31, 2012	234,059	471	(39,136)	102,133	(223)	170,814
Ending Balance, Shares at Dec. 31, 2012		47,136	2,420
Comprehensive income	89,292				581	88,711
Common stock purchased for treasury	(8,323)		(8,323)
Common stock purchased for treasury, Shares			340
Share-based compensation	8,950	6	(973)	9,917
Share-based compensation, Shares		594	40
Restricted shares forfeited			45
Exercise of stock options	16,278	12		16,266
Exercise of stock options, Shares		1,160
Excess tax benefits	4,588			4,588
Ending Balance at Dec. 31, 2013	$ 344,844	$ 489	$ (48,432)	$ 132,904	$ 358	$ 259,525
Ending Balance, Shares at Dec. 31, 2013		48,890	2,845