LEASES - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Operating leases:
Operating leases - right of use assets	$ 9,714	$ 11,775
Current operating lease obligations	2,732	6,050
Long-term operating lease obligations	7,209	5,812
Total operating lease liabilities	9,941	11,862
Finance leases:
Property and equipment, at cost	118,726	120,236
Accumulated amortization	(38,143)	(30,990)
Property and equipment, net	80,583	89,246
Current finance lease obligations	23,717	30,779
Long-term finance lease obligations	57,451	58,397
Total lease obligations	$ 81,168	$ 89,176
Weighted average remaining lease term:
Operating leases	64 months	45 months
Finance leases	39 months	44 months
Weighted average discount rate:
Operating leases	3.61%	4.03%
Finance leases	3.53%	3.34%