Real Estate and Lending Activities - Summary of Status Update on Current Development Projects (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2019 USD ($)
Business Acquisition [Line Items]
Commitment	$ 177,391
Costs Incurred as of September 30, 2019	134,079
Circle Health [Member] | Birmingham, England [Member]
Business Acquisition [Line Items]
Commitment	44,061
Costs Incurred as of September 30, 2019	$ 35,108
Estimated Rent Commencement Date	2Q 2020
Circle Health Rehabilitation [Member] | Birmingham, England [Member]
Business Acquisition [Line Items]
Commitment	$ 19,862
Costs Incurred as of September 30, 2019	$ 16,320
Estimated Rent Commencement Date	2Q 2020
Surgery Partners [Member] | Idaho Falls, ID [Member]
Business Acquisition [Line Items]
Commitment	$ 113,468
Costs Incurred as of September 30, 2019	$ 82,651
Estimated Rent Commencement Date	1Q 2020