Quarterly Consolidated Financial Data (unaudited) (Tables)

12 Months Ended

Dec. 31, 2012

Quarterly Consolidated Financial Data (unaudited) [Abstract]

Schedule of Quarterly Financial Information [Table Text Block]

	Quarters Ended
	March 31, 2011		June 30, 2011		September 30, 2011		December 31, 2011			Total
Revenues	$	50,599	$	51,543	$	41,434	$	43,620		$	187,196
Gross profit	27,297		27,859		22,254		22,943			100,353
Income (loss) before income taxes	8,150		7,930		5,333		(1,019		)	20,394
Net income	6,739		6,957		5,300		6,230			25,226
Income per share:
Basic	$	0.21	$	0.22	$	0.17	$	0.20		$	0.79
Diluted	$	0.21	$	0.22	$	0.16	$	0.19		$	0.78
Weighted average number of shares outstanding:
Basic	31,537		31,589		31,829		31,873			31,744
Diluted	32,071		32,038		32,309		32,458			32,256

	Quarters Ended
	March 31, 2012		June 30, 2012		September 30, 2012		December 31, 2012		Total
Revenues	$	45,709	$	56,326	$	62,152	$	54,299	$	218,486
Gross profit	23,765		30,222		33,125		28,563		115,675
Income before income taxes	2,873		9,931		10,571		6,032		29,407
Net income	1,862		6,346		6,661		28,996		43,865
Income per share:
Basic	$	0.06	$	0.20	$	0.21	$	0.90	$	1.36
Diluted	$	0.06	$	0.19	$	0.20	$	0.88	$	1.34
Weighted average number of shares outstanding:
Basic	32,026		32,144		32,317		32,354		32,226
Diluted	32,713		32,727		32,862		33,045		32,853