Related Party Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Rental revenues	$ 51,909	$ 46,231	$ 113,944
Property operating expenses	24,360	25,213	59,420
General and administrative	9,287	8,704	11,359
Affiliate
Related Party Transaction [Line Items]
Rental revenues	1,083
Property operating expenses	990	991	943
General and administrative	3,869	4,144	4,578
Interest income	19,515	17,413	13,132
Interest expense	1,581	1,999	423
Affiliate \| Pillar and Regis
Related Party Transaction [Line Items]
Rental revenues	1,083	841	737
Affiliate \| Regis
Related Party Transaction [Line Items]
Property operating expenses	990	991	943
Affiliate \| Pillar
Related Party Transaction [Line Items]
General and administrative	3,869	4,144	4,578
Advisory fee to related party	8,648	8,410	11,294
Interest expense	1,581	1,999	423
Affiliate \| UHF and Pillar
Related Party Transaction [Line Items]
Interest income	$ 19,515	$ 17,413	$ 13,132
Affiliate \| ARL \| MRHI
Related Party Transaction [Line Items]
Ownership interest	91.00%

The amount of advisory fees to related parties, during the period.

No definition available.

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- Definition

Amount of expense incurred and directly related to generating revenue by lessor from operating lease of rented property and equipment.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(2)(c))
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

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- Definition

The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

+ References

+ Details

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (b)
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

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- Definition

Amount before accretion (amortization) of purchase discount (premium) of interest income on nonoperating securities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.7(b))
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
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-Section 50
-Paragraph 22
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599

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- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

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- Definition

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.

+ References

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=121576215&loc=SL77919372-209981

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 45
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-URI http://asc.fasb.org/extlink&oid=121561866&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=121640914&loc=SL77927221-108306

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- Definition

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.

+ References

No definition available.

+ Details

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