LONG-TERM DEBT - Net Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2019
Interest Expense, Debt [Abstract]
Interest expense	$ 100,757	$ 101,497	$ 31,266
Amortization of deferred financing costs	3,085	3,189	2,333
Amortization of original issue discount (premium) of senior notes	(2,928)	(2,862)	(962)
Interest income and other investment income	(811)	(703)	(116)
Total net interest expense	$ 100,103	$ 101,121	$ 32,521
Weighted average interest rate under Credit Facility	4.30%	5.20%
Debt Instrument [Line Items]
Notional amount				$ 560,000