Segment Reporting - Summary of Total Assets by Segment (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Total assets	$ 42,778,765	$ 40,684,015
Multifamily [Member]
Segment Reporting Information [Line Items]
Total assets	13,634,258	13,701,615
Industrial [Member]
Segment Reporting Information [Line Items]
Total assets	12,303,484	11,498,912
Net Lease [Member]
Segment Reporting Information [Line Items]
Total assets	5,220,444	5,199,651
Hospitality [Member]
Segment Reporting Information [Line Items]
Total assets	2,343,162	2,196,429
Retail [Member]
Segment Reporting Information [Line Items]
Total assets	695,539	700,045
Self Storage [Member]
Segment Reporting Information [Line Items]
Total assets	1,553,799	1,593,430
Office [Member]
Segment Reporting Information [Line Items]
Total assets	452,944	447,630
Real Estate Debt [Member]
Segment Reporting Information [Line Items]
Total assets	4,990,532	4,763,309
Other (Corporate) [Member]
Segment Reporting Information [Line Items]
Total assets	$ 1,584,603	$ 582,994