Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Insurance reserves	$ 296,635	$ 427,843
Other	0	9,110
Deferred tax assets	296,635	436,953
Deferred tax liabilities:
Deferred policy acquisition cost	142,147	67,431
Net unrealized gain on securities	180,067	83,801
Investments	124,821	142,028
Other	4,032	0
Deferred tax liabilities	451,067	293,260
Net deferred tax asset (liability)	$ (154,432)	$ 143,693