EQUITY BASED COMPENSATION - Rockwater awards (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Restricted Stock
Assumptions for equity options granted:
Equity-based compensation expense	$ 1.9	$ 1.8
Equity options
Assumptions for equity options granted:
Equity-based compensation expense	$ 0.2	$ 1.3
Equity options | Class A Common Stock
Assumptions for equity options granted:
Underlying Equity	$ 3.23		$ 9.28