Variable Interest Entities and Other Investments - Summary of Investment in Limited Partnerships (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Variable Interest Entities and Other Investments [Line Items]
Limited partnerships required to be accounted for under the equity method	$ 12,498	$ 8,681	$ 10,208	$ 8,714
Investments in Limited Partnerships
Variable Interest Entities and Other Investments [Line Items]
Affordable housing projects (amortized cost)	27,635	28,205
Limited partnerships accounted for under the fair value practical expedient of NAV	19,785	18,742
Limited partnerships without readily determinable fair values that do not qualify for the practical expedient of NAV accounted for under the cost method	12,498	8,681
Limited partnerships required to be accounted for under the equity method	8,951	8,951
Total investments in limited partnerships	$ 68,869	$ 64,579