SCHEDULE IV - REINSURANCE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplemental Schedule of Reinsurance Premiums for Insurance Companies [Abstract]
Gross Amount	$ 1,058,545	$ 997,892	$ 950,973
Ceded to Other Companies	133,981	102,848	108,255
Assumed From Other Companies	662	1,178	1,653
Net Amount	$ 925,226	$ 896,222	$ 844,371
Percentage of Amount Assumed to Net	0.10%	0.10%	0.20%