ACCOUNTS RECEIVABLE SECURITIZATION (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Short-term Debt [Line Items]
Restricted cash	$ 6,214,000	$ 6,214,000		$ 0
Costs associated with receivables facility		1,767,000	$ 0
Line of Credit | Accounts Receivable Securitization Facility
Short-term Debt [Line Items]
Maximum borrowing capacity	100,000,000	$ 100,000,000
Security facility program fee (as a percent)		4.00%
Unused commitment fee (as a percent)		0.60%
Accounts receivable eligible for securitization	52,334,000	$ 52,334,000		60,582,000
Outstanding borrowings	0	0		0
Letters of credit outstanding	58,548,000	58,548,000		60,582,000
Borrowings and issuance of letters of credit remaining capacity	0	0		$ 0
Costs associated with receivables facility	$ 860,000	$ 1,526,000