Stock-Based Compensation (Details) (USD $)	3 Months Ended		6 Months Ended		3 Months Ended				6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012 Stock Options [Member]	Mar. 31, 2012 Stock Options [Member]	Jun. 30, 2012 Restricted Stock Units (RSUs) [Member]	Mar. 31, 2012 Restricted Stock Units (RSUs) [Member]	Jun. 30, 2012 Restricted Stock Units (RSUs) [Member]
Number of options outstanding [Roll forward]
Balances (in shares)					2,598,000	2,768,000
Granted (in shares)					19,000	43,000
Exercised (in shares)					(177,000)	(190,000)
Forfeited, cancelled or expired (in shares)					(37,000)	(23,000)
Balances (in shares)					2,403,000	2,598,000
Options vested and expected to vest (in shares)					2,320,000
Options vested (in shares)					1,982,000
Weighted Average Exercise Price [Abstract]
Balances (in dollars per share)					$ 15.71	$ 15.71
Granted (in dollars per share)					$ 27.81	$ 27.00
Exercised (in dollars per share)					$ 21.35	$ 17.63
Forfeited, cancelled or expired (in dollars per share)					$ 24.68	$ 20.38
Balances (in dollars per share)					$ 15.26	$ 15.71
Options vested and expected to vest (in dollars per share)					$ 14.90
Options vested (in dollars per share)					$ 12.69
Weighted Average Contractual Term (Years) [Abstract]
Ending balance (in years)					6.1	6.1
Options vested and expected to vest at end of period (in years)					6.0
Options vested at end of period (in years)					5.6
Aggregate Intrinsic Value [Abstract]
Ending balance					$ 39,909,000	$ 43,498,000
Options vested and expected to vest at end of period					39,064,000
Options vested at end of period					36,188,000
Weighted average grant-date fair value (in dollars per share)	$ 13.31
Total intrinsic value of options exercised	1,453,000
Net cash proceeds from the exercise of stock options	3,771,000
Assumptions used to value options granted [Abstract]
Dividend yield (in hundreths)	0.00%	0.00%	0.00%	0.00%
Annual risk free rate of return (in hundreths)	0.80%	1.90%	0.90%	2.10%
Expected volatility (in hundreths)	60.60%	53.90%	59.30%	49.10%
Expected term (years)	4.3	4.3	4.3	4.4
Vesting period of restricted stock, minimum									P3Y
Vesting period of restricted stock, maximum									P4Y
Restricted Stock Units & Awards [Roll forward]
Awarded and unvested, beginning of period (in shares)							2,683,000	1,969,000	1,969,000
Granted (in shares)							370,000	1,395,000
Vested (in shares)							(144,000)	(609,000)
Forfeited (in shares)							(81,000)	(72,000)
Awarded and unvested, ending period (in shares)							2,828,000	2,683,000	2,828,000
Restricted stock units expected to vest, Ending period (in shares)							2,329,000		2,329,000
Weighted Average Grant Date Fair Value [Abstract]
Awarded and unvested, beginning period (in dollars per share)							$ 31.61	$ 31.33	$ 31.33
Granted (in dollars per share)							$ 26.67	$ 27.60
Vested (in dollars per share)							$ 22.06	$ 21.13
Forfeited (in dollars per share)							$ 37.63	$ 34.80	$ 37.63
Awarded and unvested, ending period (in dollars per share)							$ 31.28	$ 31.61	$ 31.28
Number of restricted stock units with both performance and service vesting criteria									445,000
Unrecognized compensation expense	$ 77,399,000		$ 77,399,000
Weighted-average period of unrecognized compensation expense (in years)									3