SCHEDULE IV - REINSURANCE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental Schedule of Reinsurance Premiums for Insurance Companies [Abstract]
Gross Amount	$ 1,084,748	$ 1,059,973	$ 1,058,545
Ceded to Other Companies	111,391	125,735	133,981
Assumed From Other Companies	1,805	509	662
Net Amount	$ 975,162	$ 934,747	$ 925,226
Percentage of Amount Assumed to Net	0.20%	0.10%	0.10%