Income Taxes (Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
20% of net unearned premium	$ 75,406	$ 71,907
Discounting of loss reserves and salvage and subrogation recoverable for tax purposes	9,518	11,100
Write-down of impaired investments	857	942
Tax credit carryforward	36,349	31,198
Expense accruals	11,264	13,395
Other deferred tax assets	9,596	7,448
Total gross deferred tax assets	142,990	135,990
Deferred tax liabilities:
Deferred acquisition costs	(70,617)	(69,021)
Tax liability on net unrealized gain on securities carried at fair value	(23,095)	(47,333)
Tax depreciation in excess of book depreciation	(10,742)	(9,414)
Undistributed earnings of insurance subsidiaries	(4,022)	(4,486)
Tax amortization in excess of book amortization	(2,514)	(1,982)
Other deferred tax liabilities	(8,769)	(9,087)
Total gross deferred tax liabilities	(119,759)	(141,323)
Net deferred tax assets	23,231
Net deferred tax liabilities	$ 0	$ (5,333)