Quarterly Consolidated Financial Data (unaudited) (Tables)

12 Months Ended

Dec. 31, 2013

Quarterly Consolidated Financial Data (unaudited) [Abstract]

Schedule of Quarterly Financial Information [Table Text Block]

	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

	Quarters Ended
	March 31, 2013			June 30, 2013		September 30, 2013		December 31, 2013		Total
Revenues	$	41,650		$	46,059	$	44,044	$	44,485	$	176,238
Gross profit	21,874			23,515		22,470		22,873		90,732
Income (loss) before income taxes	(255		)	1,332		37		419		1,533
Net income	393			759		252		2,054		3,458
Income per share:
Basic	$	0.01		$	0.02	$	0.01	$	0.06	$	0.11
Diluted	$	0.01		$	0.02	$	0.01	$	0.06	$	0.10
Weighted average number of shares outstanding:
Basic	32,523			32,567		32,897		32,951		32,783
Diluted	33,239			33,155		33,426		33,539		33,388