Income Taxes (Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
20% of net unearned premiums	$ 58,448	$ 52,644
Discounting of loss reserves and salvage and subrogation recoverable for tax purposes	12,769	9,245
Write-down of impaired investments	314	356
Expense accruals	8,099	7,019
Tax asset on net unrealized loss on securities carried at fair value	0	1,055
Other deferred tax assets	3,348	3,257
Total gross deferred tax assets	82,978	73,576
Deferred tax liabilities:
Deferred policy acquisition costs	(48,964)	(45,178)
Tax liability on net unrealized gain on securities carried at fair value	(41,273)	0
Tax depreciation in excess of book depreciation	(8,105)	(4,594)
Undistributed earnings of insurance subsidiaries	(2,855)	(3,017)
Tax amortization in excess of book amortization	(3,264)	(2,729)
Other deferred tax liabilities	(6,481)	(4,719)
Total gross deferred tax liabilities	(110,942)	(60,237)
Net deferred tax (liabilities) assets	$ (27,964)
Net deferred tax (liabilities) assets		$ 13,339