Net Income per Common Share (Tables)

6 Months Ended

Jun. 30, 2011

Net Income per Common Share

Computation of basic and diluted earnings per share

		Three Months Ended June 30,				Six Months Ended June 30,
		2010		2011		2010		2011
Numerator:
Net income		$	35,428	$	34,231	$	60,947	$	68,529
Denominator:
Weighted average number of common shares outstanding—basic			33,323		31,301		33,849		32,171
	Common stock equivalents—stock options		261		523		345		508
	Common stock equivalents—warrants		142		—		146		—
	Common stock equivalents—restricted stock		13		10		17		13
	Common stock equivalents—restricted stock units		60		69		76		83
	Common stock equivalents—employee stock purchase plan		1		—		1		—
Weighted average number of common shares outstanding—diluted			33,800		31,903		34,434		32,775
Net income per common share—basic		$	1.06	$	1.09	$	1.80	$	2.13
Net income per common share—diluted		$	1.05	$	1.07	$	1.77	$	2.09