LEASES - Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019
Operating leases
Operating leases, Total future minimum lease payments, 2019	$ 3,932
Operating leases, Total future minimum lease payments, 2020	6,963
Operating leases, Total future minimum lease payments, 2021	6,100
Operating leases, Total future minimum lease payments, 2022	4,872
Operating leases, Total future minimum lease payments, 2023	3,592
Operating leases, Total future minimum lease payments, After 2023	7,088
Operating leases, Total future minimum lease payments	32,547
Operating leases, Less: interest	7,981
Operating leases, Present value of lease liabilities	24,566	$ 25,900
Finance leases
Finance leases, Total future minimum lease payments, 2019	538
Finance leases, Total future minimum lease payments, 2020	638
Finance leases, Total future minimum lease payments, 2021	0
Finance leases, Total future minimum lease payments, 2022	0
Finance leases, Total future minimum lease payments, 2023	0
Finance leases, Total future minimum lease payments, After 2023	0
Finance leases, Total future minimum lease payments	1,176
Finance leases, Less: interest	44
Finance leases, Present value of lease liabilities	1,132
Total future minimum lease payments, 2019	4,470
Total future minimum lease payments, 2020	7,601
Total future minimum lease payments, 2021	6,100
Total future minimum lease payments, 2022	4,872
Total future minimum lease payments, 2023	3,592
Total future minimum lease payments, After 2023	7,088
Total future minimum lease payments	$ 33,723