INVESTMENTS - Contractual Maturity (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Amortized Cost
Due in one year or less		$ 9.4
Due after one year through five years		98.8
Due five years through 10 years		9.7
Due after 10 years		19.3
Total	$ 137.2	218.4
Fair Value
Due in one year or less		9.4
Due after one year through five years		100.6
Due five years through 10 years		9.8
Due after 10 years		19.5
Total investments	$ 139.3	$ 224.0