SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) $ in Millions		3 Months Ended
	Jan. 01, 2018 USD ($)	Mar. 31, 2019 USD ($) segment	Mar. 31, 2018 USD ($)
Number of reportable segments | segment		1
ASU 2017-05
cumulative effect adjustment to retained earnings	$ 9.2
ASU 2016-01
Impairment of equity investments			$ 0.4
ASU 2017-08
cumulative effect adjustment to retained earnings		$ (0.3)