RECAPITALIZATION TRANSACTION - Summary of Shares Issued and Outstanding by Class of Common Stock (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended	7 Months Ended
	Nov. 09, 2018	Nov. 08, 2018	Aug. 07, 2018	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2016
Class A Common Stock
Movement In Common Stock Outstanding [Roll Forward]
Beginning balance, shares (in shares)	67,616,277	65,496,277	37,732,112
Redeemed (in shares)			(29,469,858)
Issued (in shares)	7,313,028
Converted (in shares)		2,120,000
Ending balance, shares (in shares)	74,929,305	67,616,277	65,496,277
Common stock, par value (in USD per share)				$ 0.0001	$ 0.0001
Stock redeemed value			$ 298.8
Stock issued during period related to contribution agreement	7,313,028
Class B Common Stock
Movement In Common Stock Outstanding [Roll Forward]
Beginning balance, shares (in shares)	0	9,433,028	9,433,028
Issued (in shares)	0
Forfeited (in shares)		(7,313,028)
Converted (in shares)		(2,120,000)
Ending balance, shares (in shares)	0	0	9,433,028
Common stock, par value (in USD per share)						$ 0.0001
Class C Common Stock
Movement In Common Stock Outstanding [Roll Forward]
Beginning balance, shares (in shares)	0	0	0
Issued (in shares)	250,000,000
Converted (in shares)		0
Ending balance, shares (in shares)	250,000,000	0	0
Common stock, par value (in USD per share)				$ 0.0001	$ 0.0001
Private Placement | Class A Common Stock
Movement In Common Stock Outstanding [Roll Forward]
Issued (in shares)			57,234,023