General - Basis of Presentation (Details 2) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	May 31, 2012
Details of stock benefit plans
Stock-based compensation expense	$ 7,322,000	$ 15,124,000	$ 14,419,000	$ 32,133,000
Long-Term Incentive Plan
Details of stock benefit plans
Number of shares of common stock that may be issued under the Plan					19,333,332
Maximum number of shares of common stock authorized to be issued under the Plan	28,133,332		28,133,332
Stock-based compensation expense	7,227,000	14,968,000	14,272,000	31,917,000
Shares available for future grant	6,155,000		6,155,000
Long-Term Incentive Plan | Stock options
Details of stock benefit plans
Options to purchase common stock outstanding (in shares)	9,236,000		9,236,000
Number of equal annual installments over which options outstanding are cumulatively exercisable			4
Options exercisable commencement period from grant date			1 year
Term over which options are granted			10 years
Portion of expected volatility based on historical volatility of similar entities' common stock (as a percent)			0.67
Portion of expected volatility based on historical volatility of the entity's common stock (as a percent)			0.33
Weighted-average assumptions used to estimate the fair value of stock options granted
Risk-free interest rate (as a percent)			1.19%	1.72%
Expected term			6 years 3 months	7 years 1 month 24 days
Expected volatility (as a percent)			39.21%	41.97%
Expected dividend yield (as a percent)			5.23%	4.79%
Shares
Options outstanding at the beginning of the period (in shares)			9,436,000
Granted (in shares)			282,000
Exercised (in shares)			(291,000)
Forfeited (in shares)			(190,000)
Expired (in shares)			(1,000)
Options outstanding at the end of the period (in shares)	9,236,000		9,236,000
Vested and expected to vest (in shares)	8,951,000		8,951,000
Options exercisable (in shares)	657,000		657,000
Weighted Avg. Exercise Price (in dollars per share)
Options outstanding at the beginning of the period (in dollars per share)			$ 15.04
Granted (in dollars per share)			$ 33.55
Exercised (in dollars per share)			$ 13.81
Forfeited (in dollars per share)			$ 16.89
Expired (in dollars per share)			$ 15.86
Options outstanding at the end of the period (in dollars per share)	$ 22.44		$ 22.44
Vested and expected to vest (in dollars per share)	$ 15.58		$ 15.58
Options exercisable (in dollars per share)	$ 12.79		$ 12.79
Weighted Avg. Remaining Contractual Term
Options outstanding at the end of the period			7 years 10 months 6 days
Vested and expected to vest			7 years 10 months 6 days
Options exercisable			7 years 6 months 7 days
Aggregate Intrinsic Value (in dollars)
Options outstanding at the end of the period (in dollars)	180,675,000		180,675,000
Vested and expected to vest (in dollars)	175,298,000		175,298,000
Options exercisable (in dollars)	14,693,000		14,693,000
Stock-based compensation additional disclosures
Weighted average grant date fair value of options granted (in dollars per share)			$ 7.24	$ 9.25
Total intrinsic value of options exercised (in dollars)			6,300,000	13,500,000
Fair value of options vested during the period (in dollars)			1,200,000	1,100,000
Unrecognized compensation expense (in dollars)	17,200,000		17,200,000
Weighted-average period over which unrecognized compensation cost is expected to be recognized			2 years 6 months 18 days
Cash received from the exercise of stock option			$ 4,000,000	$ 9,400,000
Long-Term Incentive Plan | Restricted stock and restricted stock units
Details of stock benefit plans
Shares outstanding under the plan	679,000		679,000