Stockholders' Equity and Noncontrolling Interests - Statutory Capital and Surplus and Net Income of Insurance Entities in Accordance with Statutory Accounting Practices (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Life insurance entities
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	$ 2,159,481		$ 2,159,770
Statutory net income (loss)	52,975	$ (7,084)
Property and casualty insurance entities
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	1,315,987		$ 1,329,782
Statutory net income (loss)	$ 48,254	$ 38,120