Real Estate Activities - Summary of Operations for Disposed Assets (Parenthetical) (Detail) € in Millions, $ in Millions		1 Months Ended	12 Months Ended
	Mar. 31, 2017 USD ($)	Aug. 31, 2018 EUR (€)	Dec. 31, 2018 USD ($)	Dec. 31, 2016 USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain on sale of real estate	$ 7.4
2018 [Member] | Germany [Member] | Acute Care Hospital [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain on sale of real estate		€ 500	$ 720.0
2016 [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain on sale of real estate				$ 60.0