Real Estate and Lending Activities - Summary of Status Update on Current Development Projects (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($)
Business Acquisition [Line Items]
Commitment	$ 179,508
Costs Incurred as of June 30, 2019	119,328
Circle Health [Member] | Birmingham, England [Member]
Business Acquisition [Line Items]
Commitment	45,520
Costs Incurred as of June 30, 2019	$ 34,452
Estimated Rent Commencement Date	1Q 2020
Circle Health Rehabilitation [Member] | Birmingham, England [Member]
Business Acquisition [Line Items]
Commitment	$ 20,520
Costs Incurred as of June 30, 2019	$ 15,564
Estimated Rent Commencement Date	1Q 2020
Surgery Partners [Member] | Idaho Falls, ID [Member]
Business Acquisition [Line Items]
Commitment	$ 113,468
Costs Incurred as of June 30, 2019	$ 69,312
Estimated Rent Commencement Date	1Q 2020