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.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
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-URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-Section S99
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-Subparagraph (SX 210.5-02(22))
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 942
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-Section S99
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Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Notes Payable - Term Loan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Unsecured term loan	$ 2,160,293	$ 2,218,093
Term Loan
Debt Instrument [Line Items]
Unsecured term loan	$ 250,000	$ 250,000
Term Loan \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	1.20%
Term Loan \| LIBOR \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	1.20%
Term Loan \| LIBOR \| Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	1.70%
Term Loan \| Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	0.50%
Term Loan \| One-month LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	1.00%
Term Loan \| Base Rate \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	0.00%
Term Loan \| Base Rate \| Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	0.75%