Stock-Based Compensation Options (Details) (USD $)	1 Months Ended	12 Months Ended
	May 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Additional shares of Class A common stock authorized for awards granted under the Omnibus Plan	2,500,000
Total shares of Class A common stock authorized for awards granted under the Omnibus Plan		6,187,500
Shares of Class A common stock available for future issuance under the Omnibus Plan Reserved for Future Issuance		2,174,314
Options Outstanding [Abstract]
Outstanding at beginning of year		1,105,411	1,460,000
Granted		199,209
Exercised		(319,732)
Expired		(521)
Forfeited		(15,035)
Outstanding at end of year		969,332	1,105,411	1,460,000
Vested or expected to vest at end of year		967,559
Exercisable at end of year		569,450
Weighted Average Exercise Price [Abstract]
Beginning of year		$ 42.61
Granted		$ 90.30
Exercised		$ 35.88
Expired		$ 39.08
Forfeited		$ 63.19
End of year		$ 54.32	$ 42.61
Vested or expected to vest at end of year		$ 54.26
Exercisable at end of year		$ 40.17
Weighted Average Remaining Contractual Term (in Years) [Abstract]
Outstanding at end of year		2 years 6 months
Vested or expected to vest at end of year		2 years 6 months
Exercisable at end of year		1 year 7 months 6 days
Aggregate Intrinsic Value [Abstract]
Outstanding at end of year		$ 40,458,000
Vested or expected to vest at end of year		40,440,000
Exercisable at end of year		31,822,000
Weighted average grant date fair value of options		$ 22.16	$ 16.25	$ 15.76
Total intrinsic value of options exercised during the year		$ 17,600,000	$ 17,300,000	$ 14,900,000