Related Party Transactions - Schedule of Related Party Expenses Incurred and Portfolio Company Incentive Compensation Awards and Capitalized Transaction Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Related Party Transaction [Line Items]
Affiliate Service Provider Expenses	$ 26,681	$ 9,599	$ 49,368	$ 17,037
Affiliate Service Provider Incentive Compensation Awards	500	500	1,000	1,000
Capitalized Transaction Support Services	740	1,563	2,629	1,963
LivCor L.L.C. [Member]
Related Party Transaction [Line Items]
Affiliate Service Provider Expenses	6,689	4,398	12,324	8,426
Affiliate Service Provider Incentive Compensation Awards	77	13	154	154
Capitalized Transaction Support Services	701	563	1,761	921
Gateway Industrial Properties L.L.C. [Member]
Related Party Transaction [Line Items]
Affiliate Service Provider Expenses		429		2,524
Affiliate Service Provider Incentive Compensation Awards				236
Capitalized Transaction Support Services				27
ShopCore Properties TRS Management L.L.C. [Member]
Related Party Transaction [Line Items]
Affiliate Service Provider Expenses	1,356	299	2,121	701
Affiliate Service Provider Incentive Compensation Awards	7	8	13	13
Capitalized Transaction Support Services			315	15
Link Industrial Properties L.L.C. [Member]
Related Party Transaction [Line Items]
Affiliate Service Provider Expenses	13,691	3,112	26,022	3,112
Affiliate Service Provider Incentive Compensation Awards	260	285	521	285
Capitalized Transaction Support Services	39	1,000	553	1,000
BRE Hotels And Resorts LLC [Member]
Related Party Transaction [Line Items]
Affiliate Service Provider Expenses	4,326	1,087	7,649	1,741
Affiliate Service Provider Incentive Compensation Awards	156	194	312	312
Revantage Corporate Services, L.L.C. [Member]
Related Party Transaction [Line Items]
Affiliate Service Provider Expenses	469	$ 274	957	$ 533
Equity Office Management, L.L.C [Member]
Related Party Transaction [Line Items]
Affiliate Service Provider Expenses	$ 150		$ 295