Income Taxes (Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
20% of net unearned premiums	$ 65,978	$ 61,067
Discounting of loss reserves and salvage and subrogation recoverable for tax purposes	18,163	15,090
Write-down of impaired investments	168	293
Expense accruals	12,997	14,432
Other deferred tax assets	5,886	6,401
Total gross deferred tax assets	103,192	97,283
Deferred tax liabilities:
Deferred policy acquisition costs	(54,234)	(51,869)
Tax liability on net unrealized gain on securities carried at fair value	(70,808)	(56,531)
Tax depreciation in excess of book depreciation	(10,129)	(12,632)
Undistributed earnings of insurance subsidiaries	(3,557)	(3,382)
Tax amortization in excess of book amortization	(6,064)	(4,666)
Other deferred tax liabilities	(11,969)	(9,335)
Total gross deferred tax liabilities	(156,761)	(138,415)
Net deferred tax liabilities	$ (53,569)	$ (41,132)