Debt (Details) - USD ($)		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Financial Instruments
Amortization of debt issuance costs		$ 6,656,000	$ 1,083,000
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Cash Flow Hedging [Member]
Financial Instruments
Notional amount of interest rate locks		1,700,000,000
Interest rate lock liability, pretax loss recognized in cumulative other comprehensive loss		23,800,000
Designated as Hedging Instrument [Member] | Other Current Liabilities [Member] | Interest Rate Contract [Member] | Cash Flow Hedging [Member]
Financial Instruments
Interest rate lock liability	[1]	23,800,000
Bridge Loan [Member] | Line of Credit [Member] | Senior Unsecured Bridge Term Loan [Member]
Financial Instruments
Maximum borrowing capacity		9,300,000,000
Bridge Loan [Member] | Line of Credit [Member] | Senior Unsecured Bridge Term Loan [Member] | Other Current Assets [Member]
Financial Instruments
Debt issuance costs		60,100,000
Bridge Loan [Member] | Line of Credit [Member] | Senior Unsecured Bridge Term Loan [Member] | Interest Expense [Member]
Financial Instruments
Amortization of debt issuance costs		5,900,000
Publicly Traded Debt [Member]
Financial Instruments
Carrying Amount		1,906,160,000	1,114,578,000
Fair Value		1,943,160,000	1,165,804,000
Non-traded debt [Member]
Financial Instruments
Carrying Amount		4,793,000	4,902,000
Fair Value		$ 4,476,000	$ 4,655,000

[1] The interest rate lock liability is measured at the present value of the expected future cash flows using market-based observable inputs.