Real Estate and Lending Activities - Assets Acquired (Parenthetical) (Detail) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016
Business Acquisition [Line Items]
Loans repaid	[1]		$ 93,262
Intangible Lease Assets - Subject to Amortization [Member]
Business Acquisition [Line Items]
Weighted average useful life of acquired intangible lease assets (in years)		28 years 8 months 12 days	19 years 4 months 24 days
Capella [Member]
Business Acquisition [Line Items]
Loans repaid			$ 93,262

[1] $93.3 million loans advanced to Capella (now RCCH Healthcare Partners ("RCCH")) in 2015 and repaid in 2016 as a part of the Capella Transaction.