LEASES - Additional Information (Details) - USD ($)	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 45,098,000		$ 0
Operating lease, liability	53,063,000
Liabilities, current	(125,868,000)		$ (141,310,000)
Finance lease, right-of-use asset	14,900,000
Secured Debt | Line of Credit | Morgan Stanley Senior Funding, Inc.
Lessee, Lease, Description [Line Items]
Face amount	$ 1,000,000.0
Minimum
Lessee, Lease, Description [Line Items]
Operating lease, term of contract	1 year
Maximum
Lessee, Lease, Description [Line Items]
Operating lease, term of contract	12 years
Accounting Standards Update 2016-02
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets		$ 34,800,000
Operating lease, liability		40,500,000
Liabilities, current		2,100,000
Liabilities, noncurrent		$ 3,600,000