Income Taxes - Significant Portions of Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Fixed maturity investments	$ 15,004	$ 16,098
Carryover of tax losses	3,906	2,266
Total gross deferred tax assets	18,910	18,364
Deferred tax liabilities:
Unrealized gains	315,509	128,683
Employee and agent compensation	92,131	83,229
Deferred acquisition costs	975,873	921,799
Future policy benefits, unearned and advance premiums, and policy claims	391,451	340,854
Other liabilities	3,987	17,176
Total gross deferred tax liabilities	1,778,951	1,491,741
Net deferred tax liability	$ 1,760,041	$ 1,473,377