LONG-TERM DEBT - Components (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Long-term debt, components
Total debt	$ 3,156,583	$ 3,259,721
Less debt issuance costs	(21,110)	(22,255)
Less debt discounts	(10,414)	(10,569)
Plus debt premiums	19,380	20,711
Total debt adjusted for discounts, premiums and debt issuance costs	3,144,439	3,247,608
Less current maturities	(78,679)	(107,903)
Long-term debt	$ 3,065,760	$ 3,139,705