LONG-TERM DEBT LIABILITIES - Debt Extinguishment and Net Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Net Interest Expense
Interest expense	$ 25,253	$ 25,626	$ 50,987	$ 48,960
Amortization of deferred financing costs	671	796	1,472	1,591
Amortization of original issue discount of senior notes	(855)	(716)	(1,570)	(1,432)
Interest income and other investment income	(125)	0	(725)	(9)
Total net interest expense	24,944	25,706	50,164	49,110
Extinguishment of Debt [Line Items]
Gains (Losses) on Extinguishment of Debt	$ (1,781)	$ 0	$ (1,781)	$ 0