NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Supplemental Information - Statement of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Income taxes paid	$ 128,168	$ 108,347	$ 106,979
Income tax refunds	1,508	12,193	196
Interest paid	203,800	191,117	182,425
Non- cash transactions
Non-cash transaction property and equipment	$ 9,500	$ 5,900
Non-cash transactions related to capital lease obligations			$ 2,800