Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net	$ (76,964)	$ (19,514)
Debt, net	2,590,331	2,195,707
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Long-term Debt, Fair Value	2,505,884	2,206,152
Recurring \| Interest rate swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Interest rate swap asset		4,297
Interest rate swap liability	(77,319)	(24,187)
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net	(77,319)	(19,890)
Recurring \| Level 1 \| Interest rate swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Interest rate swap asset		0
Interest rate swap liability	0	0
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net	0	0
Recurring \| Fair Value, Inputs, Level 2 [Member] \| Interest rate swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Interest rate swap asset		4,297
Interest rate swap liability	(77,319)	(24,187)
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net	(77,319)	(19,890)
Recurring \| Fair Value, Inputs, Level 3 [Member] \| Interest rate swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Interest rate swap asset		0
Interest rate swap liability	0	0
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net	0	0
Senior Notes [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Long-term Debt, Gross	496,940	500,484
Long-term Debt, Fair Value	467,765	497,835
Unsecured Debt [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Long-term Debt, Fair Value	1,525,375	1,176,068
Unsecured Debt	1,569,024	1,168,793
Secured Debt [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Long-term Debt, Fair Value	512,744	532,249
Secured Debt	$ 524,367	$ 526,430

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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Fair value as of the balance sheet date of all interest rate derivative assets designated as cash flow hedging instruments.

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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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Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

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