Schedule IV - Reinsurance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Premium Earned:
Gross amount	$ 748,203	$ 639,437
Ceded to other companies	(316,089)	(278,509)
Assumed from other companies	4,763	2,159
Net premiums earned	$ 436,877	$ 363,087
Percentage of amount assumed to net	1.00%	0.59%
Property, Liability and Casualty Insurance Segment [Member]
Premium Earned:
Gross amount	$ 748,203	$ 639,437
Ceded to other companies	(316,089)	(278,509)
Assumed from other companies	4,763	2,159
Net premiums earned	$ 436,877	$ 363,087
Percentage of amount assumed to net	1.00%	0.59%