SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill and Intangible Assets
Goodwill	$ 58,496	$ 58,496
Indefinite-Lived Intangible Assets (Excluding Goodwill)	7,500	8,009
Definite-lived intangible assets, net of amortization	5,298	6,190
Intangible Assets, Net (Excluding Goodwill), Total	12,798	14,199
Goodwill and intangibles	71,294	72,695
Amortization of intangible assets	900	900	$ 1,200
Contractors Bonding and Insurance Company
Goodwill and Intangible Assets
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)		1,300
RIC
Goodwill and Intangible Assets
Indefinite-lived Intangible Assets, Written off Related to Sale of Business Unit	500
Energy Surety
Goodwill and Intangible Assets
Goodwill	25,706	25,706
Miscellaneous and Contract Surety
Goodwill and Intangible Assets
Goodwill	15,110	15,110
P&C package business
Goodwill and Intangible Assets
Goodwill	5,246	5,246
Medical professional liability
Goodwill and Intangible Assets
Goodwill	$ 12,434	$ 12,434