Real Estate and Other Investments - Carrying Amount and Maximum Exposure to Loss Related to VIEs (Detail) - VIE, Not Primary Beneficiary - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Mortgage loans
Variable Interest Entity [Line Items]
Carrying amount	$ 684,991	$ 657,528
Maximum exposure to loss	684,991	657,528
Investment in unconsolidated affiliates
Variable Interest Entity [Line Items]
Carrying amount	330,527	332,742
Maximum exposure to loss	330,527	332,742
Accrued investment income
Variable Interest Entity [Line Items]
Carrying amount	2,428	2,198
Maximum exposure to loss	$ 2,428	$ 2,198