Real Estate and Other Investments - Carrying Amount and Maximum Exposure to Loss Related to VIEs (Detail) - VIE, Not Primary Beneficiary - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Mortgage Loans
Variable Interest Entity [Line Items]
Carrying amount	$ 657,528	$ 633,533
Maximum exposure to loss	657,528	633,533
Investments in Unconsolidated Affiliates
Variable Interest Entity [Line Items]
Carrying amount	332,742	330,730
Maximum exposure to loss	332,742	330,730
Accrued Investment Income
Variable Interest Entity [Line Items]
Carrying amount	2,198	2,191
Maximum exposure to loss	$ 2,198	$ 2,191