Real Estate and Lending Activities - Summary of Operations for Disposed Assets in 2018 (Parenthetical) (Detail) - Acute Care Hospital [Member] - Germany [Member] € in Millions, $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended
Aug. 31, 2018 EUR (€)	Sep. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Straight-line rent and other write-offs		$ 2.5	$ 7.6
Gain on sale of real estate	€ 500	$ 695.2	$ 719.3

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.

No definition available.

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