Equity-Based Compensation (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended								1 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Class B Common Unit [Member]		Dec. 31, 2012 Class B Common Unit [Member]	Dec. 31, 2011 Class B Common Unit [Member]	Dec. 31, 2013 2013 Long Term Incentive Plan [Member]	Oct. 31, 2007 MPK Plan Units [Member]	Dec. 31, 2013 MPK Plan Units [Member]		Dec. 31, 2013 Employee Stock Option [Member]		Dec. 31, 2013 Employee Stock Option [Member] 2013 Long Term Incentive Plan [Member]	Dec. 31, 2013 Restricted Stock [Member]	Dec. 31, 2013 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2012 Restricted Stock Units (RSUs) [Member]
Equity-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Equity-based Compensation Plan Modification, Incremental Compensation Cost						$ 6.6	$ 3.3
Accelerated share based compensation expense recognized	36.7
Payment of incentive compensation plan withholding taxes related to the acceleration of share vesting	24.0
Payment of incentive compensation plan withholding taxes, employer portion	4.0
Accrued contingent consideration	21
Number of Units Authorized								11,700,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options outstanding, number	1,280,255	0
Options outstanding, weighted-average exercise price	$ 17.00	$ 0.00
Options, Outstanding, Weighted Average Remaining Contractual Term	8 years 5 months
Options, Outstanding, Intrinsic Value	8.1
Options, Vested, Outstanding, Number	393,517
Options, Vested, Outstanding, Weighted Average Exercise Price	$ 17.00
Options, Vested, Outstanding, Weighted Average Remaining Contractual Term	8 years
Options, Vested, Outstanding, Aggregate Intrinsic Value	2.5
Options, Expected to Vest, Outstanding, Number	852,713
Options, Expected to Vest, Outstanding, Weighted Average Exercise Price	$ 17.00
Options, Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	8 years 7 months
Options, Expected to Vest, Outstanding, Aggregate Intrinsic Value	5.4
Options, Exercisable, Number	393,517
Options, Exercisable, Weighted Average Exercise Price	$ 17.00
Options, Exercisable, Weighted Average Remaining Contractual Term	8 years
Options, Exercisable, Intrinsic Value	2.5
Options, Grants in Period, Gross	1,288,398											1,268,986		19,412
Options, Forfeitures and Expirations in Period	(8,143)
Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$ 17.00
Options, Exercises in Period	0
Options, Exercises in Period, Weighted Average Exercise Price	$ 0.00
Options, Grants in Period, Weighted Average Exercise Price	$ 17.00											$ 17.00
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Equity Instruments Other than Options, Nonvested, Number															2,592,033	1,351,572	0
Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value				$ 119.00		$ 125.65	$ 148.89		$ 1,000.00							$ 17.03
Equity Instruments Other Than Options, Vested in Period															(1,200,544)	(1,844)
Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value																$ 17.00
Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value																$ 17.01
Equity Instruments Other than Options, Vested in Period, Fair Value	26.7
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value																$ 17.04	$ 0.00
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period									10 years 0 months 0 days							4 years
Equity-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Options, Grants in Period, Weighted Average Grant Date Fair Value												$ 4.75
Weighted-Average Volatility				65.50%		65.26%	82.87%					35.00%	[1]
Weighted-Average Risk-Free Rate				0.18%		0.19%	0.84%					1.58%	[2]
Dividend Yield				0.00%		0.00%	0.00%					1.00%
Fair Value Assumptions, Expected Term												5 years 5 months	[3]
Equity-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Equity Awards Outstanding, Beginning of Year				216,483						66,137
Equity Awards Granted				400						0					3,798,508	1,416,543
Equity Awards Forfeited				(860)						(2,228)					(5,931)	(63,127)
Equity Awards Repurchased/Settled				(216,023)	[4]					(63,909)	[4]
Equity Awards Outstanding, End of Period				0		216,483				0
Equity Awards Vested				0						0
Equity-based compensation [Abstract]
Equity-based compensation expense	46.6	22.1	19.5
Equity-based Compensation Expense, Tax Benefit from Compensation Expense	16.5	2.3	1.9
Equity-based Compensation Expense, Capitalized Amount	0	0	0
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized [Abstract]
Equity-based Compensation Expense Not yet Recognized	$ 24.9
Equity-based Compensation Expense Not yet Recognized, Period for Recognition	3 years 3 months 15 days

[1] Based upon an assessment of the two-year, five-year and implied volatility for the Company’s selected peer group, adjusted for the Company’s leverage.

[2] Based on a composite U.S. Treasury rate.

[3] The expected term is calculated using the simplified method. The simplified method defines the expected term as the average of the option’s contractual term and the option’s weighted-average vesting period. The Company utilizes this method as it has limited historical stock option data that is sufficient to derive a reasonable estimate of the expected stock option term.

[4] As discussed above, the Class B Common Units and MPK Plan Units were converted/settled into shares of the Company's common stock upon completion of the IPO. The converted Class B Common Units, to the extent unvested at the time of the IPO, relate to the grants of restricted stock disclosed above.