Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets
State income taxes, net of federal impact	$ 77,637	$ 75,499
Goodwill and intangibles	29,744	32,673
Unearned premiums	23,699	27,703
Accrued expenses	16,584	11,140
Lease liability	11,240	11,214
Loss reserves	6,286	4,578
Other	18,967	25,066
Total deferred tax assets	184,157	187,873
Deferred tax liabilities
Contingency reserve	368,000	216,122
Net unrealized gain on investments	31,876	70,057
Depreciation	12,775	13,029
Differences in fair value of financial instruments	7,763	9,087
Other	17,824	15,747
Total deferred tax liabilities	438,238	324,042
Less: Valuation allowance	83,428	77,728
Net deferred tax asset (liability)	$ (337,509)	$ (213,897)