LONG TERM DEBT (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016
Long-Term Debt
Total debt before unamortized discount and debt issuance costs	$ 460,956				$ 489,355
Unamortized discount	(5,556)				(7,511)
Debt issuance costs, net	(5,136)				(9,194)
Total debt	450,264				472,650
Current portion of long-term debt	4,336	$ 13,129	$ 21,476	$ 27,398	30,944	$ 28,833	$ 29,713	$ 29,447
Long-term debt	445,928	$ 474,434	$ 462,339	$ 456,663	441,706	$ 457,021	$ 519,952	$ 525,521
Credit Agreement
Long-Term Debt
Total debt before unamortized discount and debt issuance costs	151,900
Credit Agreement | Term Loan
Long-Term Debt
Total debt before unamortized discount and debt issuance costs	151,875				180,000
Credit Agreement | Term Loan B
Long-Term Debt
Total debt before unamortized discount and debt issuance costs	280,000				280,000
Credit Agreement | Revolving Credit Facility
Long-Term Debt
Total debt before unamortized discount and debt issuance costs	5,000				0
Term B Credit Agreement
Long-Term Debt
Debt issuance costs, net					(6,700)
Term B Credit Agreement | Term Loan B
Long-Term Debt
Total debt before unamortized discount and debt issuance costs	280,000				280,000
Seller notes
Long-Term Debt
Total debt before unamortized discount and debt issuance costs	5,912				11,110
Unamortized discount	(300)				(600)
Financing leases and other
Long-Term Debt
Total debt before unamortized discount and debt issuance costs	$ 18,169				$ 18,245