Segment Reporting - Summary of Total Assets by Segment (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Total assets	$ 37,032,808	$ 33,039,823
Multifamily [Member]
Segment Reporting Information [Line Items]
Total assets	11,421,928	9,695,916
Industrial [Member]
Segment Reporting Information [Line Items]
Total assets	11,199,187	10,564,172
Net Lease [Member]
Segment Reporting Information [Line Items]
Total assets	5,054,612	4,271,196
Hotel [Member]
Segment Reporting Information [Line Items]
Total assets	2,227,264	2,427,554
Retail [Member]
Segment Reporting Information [Line Items]
Total assets	707,605	419,198
Other Properties [Member]
Segment Reporting Information [Line Items]
Total assets	257,458	145,411
Office [Member]
Segment Reporting Information [Line Items]
Total assets	132,303	138,912
Real Estate Debt [Member]
Segment Reporting Information [Line Items]
Total assets	5,723,230	4,565,385
Other (Corporate) [Member]
Segment Reporting Information [Line Items]
Total assets	$ 309,221	$ 812,079