Net Income per Common Share (Tables)

9 Months Ended

Sep. 30, 2011

Net Income per Common Share

Computation of basic and diluted earnings per share

		Three Months Ended September 30,				Nine Months Ended September 30,
		2010		2011		2010		2011
Numerator:
Net income		$	44,784	$	31,355	$	105,731	$	99,884
Denominator:
Weighted average number of common shares outstanding—basic			33,450		29,900		33,715		31,406
	Common stock equivalents—stock options		475		446		389		487
	Common stock equivalents—warrants		157		—		150		—
	Common stock equivalents—restricted stock		6		4		13		10
	Common stock equivalents—restricted stock units		83		88		78		85
	Common stock equivalents—employee stock purchase plan		—		—		—		—
Weighted average number of common shares outstanding—diluted			34,171		30,438		34,345		31,988
Net income per common share—basic		$	1.34	$	1.05	$	3.14	$	3.18
Net income per common share—diluted		$	1.31	$	1.03	$	3.08	$	3.12