ASBESTOS AND ENVIRONMENTAL CLAIMS (Details) $ in Thousands	12 Months Ended	108 Months Ended
	Dec. 31, 2017 USD ($) policyholder claim lawsuit	Dec. 31, 2017 USD ($) claim lawsuit	Dec. 31, 2016 USD ($)
Liability for Asbestos and Environmental Claims [Abstract]
Average asbestos and environmental losses paid by company per year over past five years	$ 2,900
Reserves for asbestos and environmental related claims, before reinsurance	11,700	$ 11,700	$ 13,300
Reserves for asbestos and environmental related claims, net of reinsurance	$ 11,400	$ 11,400	$ 13,000
Number of asbestos bodily injury lawsuits | lawsuit	1,872	1,872
Number of policyholders producing recent higher paid asbestos amounts | policyholder	1
Company's share of asbestos related claims settled		$ 12,500
Number of asbestos exposure claims associated with furnace manufacturer, a former policyholder, remain open | claim	692	692
Payments for legal settlements	$ 4,500
Asbestos reserve strengthening	$ 900