LEASES - Components of expense and supplemental cash flow information (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Operating
Fixed operating lease expense	$ 6,265	$ 19,561
Variable operating lease expense	2,860	9,211
Total operating lease expense	9,125	28,772
Cash paid for amounts included in the measurement of operating lease liabilities		9,884
ROU assets obtained in exchange for operating lease obligations		0
Finance
Amortization of right of use assets	3,919	11,753
Interest expense	434	1,484
Total finance lease expense	$ 4,353	$ 13,237
Weighted average remaining lease term (in years)	1 year 7 months 2 days	1 year 7 months 2 days
Weighted average discount rate	5.37%	5.37%