Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data	Total	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]
Balance - beginning of year at Dec. 31, 2008	$ 114,506	$ 94,882	$ (8)	$ 1,824	$ 0	$ 17,808
Balance - beginning of year (in shares) at Dec. 31, 2008				27,374,020
Net earnings	26,785	26,785	0	0	0	0
Other comprehensive income (loss)	161	0	161	0	0	0
Dividends	(3,091)	(3,091)	0	0	0	0
Shares issued under employee benefit plans and other	430	0	0	2	0	428
Shares issued under employee benefit plans and other (in shares)				24,413
Shares and options issued under stock plans and an income tax benefit	8,352	0	0	47	0	8,305
Shares and options issued under stock plans (in shares)				698,846
Balance - end of year at Dec. 31, 2009	147,143	118,576	153	1,873	0	26,541
Balance - end of year (in shares) at Dec. 31, 2009				28,097,279
Net earnings	33,277	33,277	0	0	0	0
Other comprehensive income (loss)	(702)	0	(702)	0	0	0
Dividends	(4,311)	(4,311)	0	0	0	0
Treasury shares purchased	(937)	0	0	0	(937)	0
Treasury shares purchased (in shares)					(29,143)
Shares issued under employee benefit plans and other	431	0	0	1	0	430
Shares issued under employee benefit plans and other (in shares)				17,065
Shares and options issued under stock plans and an income tax benefit	12,566	0	0	43	937	11,586
Shares and options issued under stock plans (in shares)				637,981	29,143
Balance - end of year at Dec. 31, 2010	187,467	147,542	(549)	1,917	0	38,557
Balance - end of year (in shares) at Dec. 31, 2010	0			28,752,325	0
Net earnings	38,765	38,765	0	0	0	0
Other comprehensive income (loss)	(389)	0	(389)	0	0	0
Dividends	(5,237)	(5,237)	0	0	0	0
Treasury shares purchased	(109)	0	0	0	(109)	0
Treasury shares purchased (in shares)					(19,545)
Shares issued under employee benefit plans and other	475	0	0	1	51	423
Shares issued under employee benefit plans and other (in shares)				10,962	1,280
Shares and options issued under stock plans and an income tax benefit	11,037	0	0	26	58	10,953
Shares and options issued under stock plans (in shares)				402,434	18,265
Balance - end of year at Dec. 31, 2011	$ 232,009	$ 181,070	$ (938)	$ 1,944	$ 0	$ 49,933
Balance - end of year (in shares) at Dec. 31, 2011				29,165,721	0