Real Estate Activities - Assets Acquired (Parenthetical) (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Loans repaid	[1]		$ 764,447
Weighted average useful life of acquired intangible lease assets (in years)		21 years 7 months 6 days
Intangible Lease Assets - Subject to Amortization [Member]
Business Acquisition [Line Items]
Weighted average useful life of acquired intangible lease assets (in years)		19 years 1 month 6 days	27 years 10 months 24 days	27 years 8 months 12 days
Steward [Member]
Business Acquisition [Line Items]
Loans repaid			$ 800,000

[1] The 2018 column includes $0.8 billion of loans advanced to Steward in 2016 and repaid in 2018 as part of sale leaseback conversion described below.