Leases - Narrative (Details) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($) renewal_option	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Leases [Abstract]
Rental income	$ 462,225
Rental income		$ 442,397	$ 416,978
Approximate Investment in real estate properties subject to outstanding contractual option to purchase	$ 96,000
Number of exercisable purchase options \| renewal_option	4

Amount of operating lease income from lease payments and variable lease payments paid and payable to lessor. Includes, but is not limited to, variable lease payments not included in measurement of lease receivable.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=119202524&loc=SL77919372-209981

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=77888421&loc=SL77919311-209978

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section 50
-Paragraph 6A
-URI http://asc.fasb.org/extlink&oid=118952077&loc=SL77927221-108306

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration