SCHEDULE IV - REINSURANCE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract]
Gross Amount	$ 1,199,824	$ 1,155,240	$ 1,084,748
Ceded to Other Companies	188,729	129,337	111,391
Assumed From Other Companies	10,848	5,085	1,805
Net Amount	$ 1,021,943	$ 1,030,988	$ 975,162
Percentage of Amount Assumed to Net	1.10%	0.50%	0.20%