LONG-TERM DEBT LIABILITIES - Debt Extinguishment and Net Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net Interest Expense
Interest expense	$ 25,734	$ 23,334
Amortization of deferred financing costs	801	795
Amortization of original issue discount of senior notes	(715)	(716)
Interest income and other investment income	(600)	(9)
Total net interest expense	$ 25,220	$ 23,404