Schedule VI - Supplemental Information Concerning Property and Casualty Insurance Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Supplemental Information Concerning Property and Casualty Insurance Operations
Earned Premiums	$ 788,777	$ 781,587	$ 774,420
Current year	551,895	542,001	545,671
Prior year	(42,049)	(56,488)	(41,784)
Consolidated Property & Casualty Subsidiaries
Supplemental Information Concerning Property and Casualty Insurance Operations
Deferred Policy Acquisition Costs	74,287	73,355	72,202
Reserves for Unpaid Claims and Claims Adjustment Expenses	610,566	584,719	574,054
Unearned Premiums	442,219	435,380	428,257
Earned Premiums	788,777	781,587	774,420
Net Investment Income	46,665	43,788	38,758
Current year	551,895	542,001	545,671
Prior year	(42,049)	(56,488)	(41,784)
Amortization of Deferred Policy Acquisition Costs	147,945	146,601	144,703
Paid Claims and Claims Adjustment Expenses	497,973	500,161	489,515
Premiums Written	$ 794,409	$ 786,912	$ 781,054