Income Taxes - Significant Portions of Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Fixed maturity investments	$ 6,161	$ 6,131
Carryover of tax losses	7,827	7,406
Total gross deferred tax assets	13,988	13,537
Deferred tax liabilities:
Unrealized gains	493,174	87,871
Employee and agent compensation	81,174	70,551
Deferred acquisition costs	658,457	633,687
Future policy benefits, unearned and advance premiums, and policy claims	242,124	242,285
Other liabilities	26,271	25,603
Total gross deferred tax liabilities	1,501,200	1,059,997
Deferred Tax Liabilities, Net, Total	$ 1,487,212	$ 1,046,460