Real Estate and Other Investments - Assets and Liabilities Related to VIEs (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Investment real estate	$ 545,646	$ 551,219
Short-term investments	418,882	425,321
Cash and cash equivalents	328,752	452,001
Other assets	187,950	171,285
Total assets	27,838,813	28,597,566
Notes payable	156,943	157,997
Other liabilities	478,728	446,882
Total liabilities	22,231,724	22,601,803
VIE, Primary Beneficiary
Variable Interest Entity [Line Items]
Investment real estate	134,148	134,534
Short-term investments	501	500
Cash and cash equivalents	9,843	11,155
Other receivables	3,030	3,673
Other assets	14,238	15,355
Total assets	161,760	165,217
Notes payable	156,943	157,997
Other liabilities	9,210	9,731
Total liabilities	$ 166,153	$ 167,728