Summary of Significant Accounting Policies - Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Assets:
Equity securities	$ 1,001,297	$ 599,185
Derivatives	46,345
Liabilities:
Derivatives	14,945	55,536
Recurring [Member]
Assets:
Investments in real estate debt	4,896,416	4,566,306
Equity securities	1,001,297	599,185
Investments in unconsolidated entities	383,343
Derivatives	46,345
Total	6,327,401	5,165,491
Liabilities:
Derivatives	14,945	55,536
Total	14,945	55,536
Recurring [Member] | Level 1 [Member]
Assets:
Equity securities	578,496	327,935
Total	578,496	327,935
Recurring [Member] | Level 2 [Member]
Assets:
Investments in real estate debt	4,724,374	4,445,414
Equity securities	422,801	271,250
Derivatives	46,345
Total	5,193,520	4,716,664
Liabilities:
Derivatives	14,945	55,536
Total	14,945	55,536
Recurring [Member] | Level 3 [Member]
Assets:
Investments in real estate debt	172,042	120,892
Investments in unconsolidated entities	383,343
Total	$ 555,385	$ 120,892