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Debt Instrument, Margin

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Debt Instrument, Unamortized Discount (Premium) and Deferred Financing Costs, Net

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Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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Including the current and noncurrent portions, carrying amount of debt identified as being convertible into another form of financial instrument (typically the entity's common stock) as of the balance sheet date, which originally required full repayment more than twelve months after issuance or greater than the normal operating cycle of the company.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion.

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The price per share of the conversion feature embedded in the debt instrument.

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Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

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Face (par) amount of debt instrument at time of issuance.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount, after accumulated amortization, of debt discount.

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Weighted average interest rate of debt outstanding.

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Amount of interest capitalized during the period.

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Debt Obligations, net (Schedule of Debt) (Details) - USD ($)	1 Months Ended		3 Months Ended		7 Months Ended
	Sep. 30, 2017	Jan. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Oct. 31, 2017	Oct. 20, 2017	Aug. 31, 2016	Jun. 30, 2016
Debt Instrument [Line Items]
Total debt obligations			$ 3,190,333,000			$ 3,539,991,000
Debt discounts and deferred financing costs, net			(59,399,000)			(63,591,000)
Total debt obligations, net			3,130,934,000			3,476,400,000
Interest costs capitalized			2,400,000	$ 2,000,000
2015 $325 million Revolving Credit Facility
Debt Instrument [Line Items]
Debt instrument, face amount			325,000,000
Total debt obligations			$ 0			325,000,000
Converted term loan, term			1 year
2015 $325 million Revolving Credit Facility \| Minimum \| Interest Rate Category One
Debt Instrument [Line Items]
Debt instrument, margin (as a percent)			1.25%
2015 $325 million Revolving Credit Facility \| Minimum \| Interest Rate Category Two
Debt Instrument [Line Items]
Debt instrument, margin (as a percent)			2.25%
2015 $325 million Revolving Credit Facility \| Maximum \| Interest Rate Category One
Debt Instrument [Line Items]
Debt instrument, margin (as a percent)			1.75%
2015 $325 million Revolving Credit Facility \| Maximum \| Interest Rate Category Two
Debt Instrument [Line Items]
Debt instrument, margin (as a percent)			2.75%
2015 $325 million Revolving Credit Facility \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis point spread on variable interest rate (as a percent)			2.50%
2015 $325 million Revolving Credit Facility \| London Interbank Offered Rate (LIBOR) \| Minimum
Debt Instrument [Line Items]
Basis point spread on variable interest rate (as a percent)			1.00%
2015 $325 million Revolving Credit Facility \| Federal Funds Effective Swap Rate
Debt Instrument [Line Items]
Basis point spread on variable interest rate (as a percent)			0.50%
2016 Senior Credit Facility
Debt Instrument [Line Items]
Debt instrument, face amount	$ 400,000,000.0								$ 500,000,000.0	$ 450,000,000.0
Total debt obligations			$ 376,671,000			399,000,000
Basis point spread on variable interest rate (as a percent)			1.00%
2016 Senior Credit Facility \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis point spread on variable interest rate (as a percent)	3.00%	3.75%	3.00%		4.50%
2016 Senior Credit Facility \| London Interbank Offered Rate (LIBOR) \| Minimum
Debt Instrument [Line Items]
Basis point spread on variable interest rate (as a percent)	0.75%	1.00%	0.75%		1.00%
2016 Senior Credit Facility \| London Interbank Offered Rate (LIBOR) \| Maximum
Debt Instrument [Line Items]
Basis point spread on variable interest rate (as a percent)			2.00%
2016 Senior Credit Facility \| Federal Funds Effective Swap Rate
Debt Instrument [Line Items]
Basis point spread on variable interest rate (as a percent)			0.50%
Mortgages collateralized by net lease assets
Debt Instrument [Line Items]
Total debt obligations			$ 206,162,000			208,491,000
Weighted average interest rate (as a percent)			5.20%
Mortgages collateralized by net lease assets \| Minimum
Debt Instrument [Line Items]
Stated interest rates (as a percent)			4.102%
Mortgages collateralized by net lease assets \| Maximum
Debt Instrument [Line Items]
Stated interest rates (as a percent)			7.26%
Total secured credit facilities and mortgages
Debt Instrument [Line Items]
Total debt obligations			$ 582,833,000			932,491,000
5.00% senior notes
Debt Instrument [Line Items]
Total debt obligations			$ 770,000,000			770,000,000
Stated interest rates (as a percent)			5.00%
4.625% senior notes
Debt Instrument [Line Items]
Debt instrument, face amount	$ 400,000,000.0
Total debt obligations			$ 400,000,000			400,000,000
Stated interest rates (as a percent)	4.625%		4.625%
6.50% senior notes
Debt Instrument [Line Items]
Total debt obligations			$ 275,000,000			275,000,000
Stated interest rates (as a percent)			6.50%
6.00% senior notes
Debt Instrument [Line Items]
Debt instrument, face amount				$ 375,000,000.0
Total debt obligations			$ 375,000,000			375,000,000
Stated interest rates (as a percent)			6.00%	6.00%
5.25% senior notes
Debt Instrument [Line Items]
Debt instrument, face amount	$ 400,000,000.0
Total debt obligations			$ 400,000,000			400,000,000
Stated interest rates (as a percent)	5.25%		5.25%
3.125% senior convertible notes
Debt Instrument [Line Items]
Debt instrument, face amount	$ 250,000,000.0						$ 37,500,000	$ 37,500,000
Total debt obligations			$ 287,500,000			287,500,000
Total debt obligations, net			$ 258,200,000
Stated interest rates (as a percent)	3.125%		3.125%				3.125%	3.125%
Convertible debt, conversion ratio (in shares per par value)			64.36
Convertible debt, conversion price (in dollars per share)			$ 15.54
Liability component of convertible debt	$ 221,800,000						$ 34,000,000
Carrying value of equity component of convertible debt	$ 22,500,000						$ 3,400,000
Debt Instrument, Unamortized Discount			$ 24,000,000
Interest Expense, Debt			2,200,000
Amortization of Debt Discount (Premium)			$ 1,200,000
Effective interest rate			5.20%
Unsecured Notes
Debt Instrument [Line Items]
Total debt obligations			$ 2,507,500,000			2,507,500,000
Trust preferred securities
Debt Instrument [Line Items]
Total debt obligations			$ 100,000,000			$ 100,000,000
Basis point spread on variable interest rate (as a percent)			1.50%