Quarterly Financial Information (Tables)

12 Months Ended

Dec. 31, 2011

Quarterly Financial Information [Abstract]

Summary Of Selected Financial Information

	Quarters Ended
	2011								2010
	Dec. 31		Sept. 30		June 30		Mar. 31		Dec. 31		Sept. 30		June 30		Mar. 31
Revenues	$	82,079	$	77,184	$	76,735	$	73,393	$	72,439	$	73,769	$	72,600	$	69,820
Gross profit		39,020		36,132		34,137		32,623		32,616		33,207		32,475		30,019
Income before income taxes		13,504		11,818		9,309		9,482		10,159		11,263		10,383		8,094
Net income		8,699		7,506		5,624		5,728		7,210		6,723		6,249		4,872
Earnings per diluted share		0.27		0.23		0.17		0.17		0.21		0.19		0.17		0.13
Shares used in computing diluted earnings per share		32,031		32,960		33,848		33,720		33,895		35,410		36,203		36,655