INVESTMENTS (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($) security	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($) security
Investments [Abstract]
Proceeds from sale of investment securities	$ 78.1	$ 128.6
Unrealized gains and losses for equity securities (Less Than)	$ 0.1
Debt and equity securities held in an unrealized loss position | security	1,346		866
Debt securities and equity securities held in an unrealized loss position 12 months or more | security	52		73
Fair value of investments deposited with governmental authorities required by law	$ 12.8		$ 12.9