General - Basis of Presentation (Details 3) (USD $)	1 Months Ended		3 Months Ended		9 Months Ended		1 Months Ended		3 Months Ended		9 Months Ended					9 Months Ended					12 Months Ended	9 Months Ended	3 Months Ended		9 Months Ended
	Aug. 31, 2012	Jun. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Chief Operating Officer	Feb. 08, 2012 Dividend equivalent rights	Sep. 30, 2012 Long-Term Incentive Plan	Sep. 30, 2011 Long-Term Incentive Plan	Sep. 30, 2012 Long-Term Incentive Plan	Sep. 30, 2011 Long-Term Incentive Plan	Sep. 30, 2012 Long-Term Incentive Plan Stock options Y	Sep. 30, 2011 Long-Term Incentive Plan Stock options	Dec. 31, 2011 Long-Term Incentive Plan Stock options	Sep. 30, 2012 Long-Term Incentive Plan Stock, restricted stock awards and restricted stock units	Sep. 30, 2011 Long-Term Incentive Plan Stock, restricted stock awards and restricted stock units	Sep. 30, 2012 Long-Term Incentive Plan Restricted stock awards Y	Sep. 30, 2012 Long-Term Incentive Plan Performance award based on the EBITDA performance of the Company in 2011 and 2012 Key employees	Sep. 30, 2012 Long-Term Incentive Plan Performance award based on the EBITDA performance of the Company in 2012-2015	Dec. 31, 2011 Long-Term Incentive Plan Performance award based on the EBITDA performance of the Company in 2012-2015 Key employees	Sep. 30, 2012 Long-Term Incentive Plan Deferred stock units D	Sep. 30, 2012 Employee Stock Purchase Plan	Sep. 30, 2011 Employee Stock Purchase Plan	Sep. 30, 2012 Employee Stock Purchase Plan M	Sep. 30, 2011 Employee Stock Purchase Plan	Sep. 30, 2012 Employee Stock Purchase Plan Stock options
Details of stock benefit plans
Restricted stock units to be forfeited if performance criteria is not met (as a percent)																			50.00%
Potential award grant based on achievement of performance criteria (in shares)																					1,325,000
Unrecognized compensation expense (in dollars)													$ 29,700,000					$ 13,400,000		$ 77,900,000
Unvested stock options outstanding (in shares)								5,000,000
Dividend equivalent rights threshold for accumulated accrued dividend distribution					1,000
Additional options granted by Board of Directors	1,000,000
Stock split ratio		2
Dividend in form of number of shares for each outstanding share of common stock		1
Options to purchase common stock outstanding or purchase rights outstanding (in shares)													5,202,000		5,732,000												9,000
Total intrinsic value of options exercised or purchase rights (in dollars)													50,900,000	5,000,000													100,000
Shares
Non-vested balance at the beginning of the period (in shares)																548,000
Granted (in shares)																1,467,000						2,000
Vested (in shares)																(181,000)
Forfeited (in shares)							41,000									(62,000)
Non-vested balance at the end of the period (in shares)																1,772,000						2,000
Weighted Average Grant Date Fair Value Per Share (in dollars per share)
Non-vested shares at the beginning of the period (in dollars per share)																$ 18.74
Granted (in dollars per share)																$ 45.84	$ 35.13					$ 48.40
Vested (in dollars per share)																$ 19.35
Forfeited (in dollars per share)																$ 35.72
Non-vested shares at the end of the period (in dollars per share)																$ 40.52
Total grant date fair value of the stock awards granted (in dollars)																67,300,000	800,000					100,000
Total fair value of stock awards that vested during the period (in dollars)																3,500,000	3,900,000
Weighted-average period over which unrecognized compensation cost is expected to be recognized (in years)													3.1					0.7
Number of shares to be issued for each award																						1
Maximum number of shares of common stock authorized to be issued under the Plan									14,066,666		14,066,666
Period following cessation of the non-employee director's service after which shares are to be delivered (in days)																						30
Percentage of the market value of common stock at beginning or end of the offering period for shares eligible to be purchased																							90.00%		90.00%
Successive offering period under Plan (in months)																									6
Number of shares of common stock that may be issued under the Plan									9,666,666		9,666,666												1,000,000		1,000,000
Shares available for future grant									3,104,000		3,104,000												968,000		968,000
Share-based compensation general disclosures
Stock-based compensation expense			12,751,000	6,652,000	44,884,000	34,316,000			12,708,000	6,612,000	44,625,000	34,156,000											43,000	40,000	259,000	160,000
Stock-based compensation for dividend equivalent rights											$ 4,000,000