Schedule III - Real Estate and Accumulated Depreciation and Amortization Part 21 (Parenthetical) (Detail)	12 Months Ended
Dec. 31, 2018
Minimum [Member]
Schedule Of Investments In Real Estate [Line Items]
Estimated useful lives of the assets	16 years
Maximum [Member]
Schedule Of Investments In Real Estate [Line Items]
Estimated useful lives of the assets	25 years

Useful life on which depreciation was computed for entities with a substantial portion of business acquiring and holding investment real estate, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 970
-SubTopic 360
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-28(Column I))
-URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration