Quarterly Consolidated Financial Data (unaudited) (Tables)

12 Months Ended

Dec. 31, 2015

Quarterly Consolidated Financial Data (unaudited) [Abstract]

Schedule of Quarterly Financial Information [Table Text Block]

	Quarters Ended
	March 31, 2015		June 30, 2015		September 30, 2015		December 31, 2015		Total
Revenues	$	52,570	$	59,466	$	58,597	$	51,057	$	221,690
Gross profit	28,966		31,884		31,912		26,644		119,406
Income before income taxes	3,097		8,656		10,880		4,179		26,812
Net income	1,848		6,027		7,198		2,883		17,956
Income per share:
Basic	$	0.06	$	0.19	$	0.23	$	0.09	$	0.57
Diluted	$	0.06	$	0.19	$	0.22	$	0.09	$	0.56
Weighted average number of shares outstanding:
Basic	31,928		31,663		31,526		31,016		31,408
Diluted	32,549		32,339		32,204		32,075		32,166

	Quarters Ended
	March 31, 2014			June 30, 2014			September 30, 2014			December 31, 2014		Total
Revenues	$	41,649		$	43,018		$	46,960		$	49,591	$	181,218
Gross profit	21,569			23,304			24,960			25,655		95,488
Income (loss) before income taxes	(1,041		)	(10,995		)	2,835			2,510		(6,691		)
Net income	(724		)	(4,412		)	(998		)	1,494		(4,640		)
Income per share:
Basic	$	(0.02	)	$	(0.13	)	$	(0.03	)	$	0.05	$	(0.14	)
Diluted	$	(0.02	)	$	(0.13	)	$	(0.03	)	$	0.04	$	(0.14	)
Weighted average number of shares outstanding:
Basic	33,092			33,240			33,237			32,882		33,124
Diluted	33,092			33,240			33,237			33,504		33,124