Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2012

Stockholders' Equity [Abstract]

Summary of Stock option activity

	Number of Shares			Weighted - Average Exercise Price Per Share		Weighted - Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2011		2,130		$	27.46
Granted		422			33.25
Exercised		(435	)		24.47
Forfeited		(181	)		31.44
Outstanding at December 31, 2012		1,936		$	29.03		6.37	$	2,319
Vested and expected to vest at December 31, 2012		1,859		$	28.86		6.27	$	2,316
Exercisable at December 31, 2012		1,096		$	26.48		4.73	$	2,151

Details of Restricted Stock Units (RSU) activity

	Number of Shares			Weighted- Average Grant Date Fair Value
Unvested at December 31, 2011		267		$	29.93
Granted		179			33.88
Vested or settled		(49	)		27.60
Forfeited		(96	)		28.90
Unvested at December 31, 2012		301		$	32.98

Summary of Shares purchased by employees under the Stock Purchase Plan

	Shares		Purchase
Purchase Period Ended	Purchased		Price
August 31, 2012		23	$	24.88
June 30, 2011		51	$	28.02
December 31, 2011		50	$	28.08
June 30, 2010		45	$	22.67
December 31, 2010		44	$	26.44