Share-Based Compensation (Details) - USD ($)	1 Months Ended	9 Months Ended
	Feb. 26, 2015	Sep. 30, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to nonvested share-based compensation arrangements		$ 45,600,000
Compensation expense over a remaining weighted-average period		1 year 8 months 12 days
Restricted Stock Units and Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of restricted stock granted	$ 22,500,000
Awards vesting period	3 years
Aggregate grant date fair value, net of estimated forfeitures	$ 21,200,000
Requisite service period	2 years 8 months 12 days
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards vesting period	3 years
Target value of p-units granted during the period (in dollars per unit)	$ 100
Total shareholder return, Minimum payout (in dollars per unit)	$ 0
Total shareholder return, Maximum payout (in dollars per unit)	$ 200
Vesting percentage based on relative total shareholder return ranking on annual basis		25.00%
Vesting percentage of performance units periodically (in hundredths)		25.00%
Grant date fair value of P-Units		$ 9,000,000
Performance measurement period		3 years
Estimated liabilities outstanding for share-based compensation award		$ 16,100,000	$ 11,600,000