Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2011

Quarterly Financial Data - Unaudited [Abstract]

Schedule of Quarterly Financial Information [Table Text Block]

	Quarter Ended
	March 31		June 30		Sept. 30		Dec. 31
2011
Total revenue	$	71,471	$	77,796	$	76,458	$	76,470
Gross profit	34,626		36,201		35,574		35,953
Net income	8,073		9,493		9,261		17,842
Net income per share:
Basic	$	0.59	$	0.69	$	0.66	$	1.29
Diluted	$	0.57	$	0.67	$	0.65	$	1.26
2010 (restated)
Total revenue	$	63,723	$	68,625	$	75,482	$	75,129
Gross profit	26,287		31,890		33,777		37,016
Net income	3,859		7,566		8,817		9,681
Net income per share:
Basic	$	0.28	$	0.56	$	0.65	$	0.71
Diluted	$	0.27	$	0.55	$	0.64	$	0.70