LEASES - Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019
Operating leases
Operating leases, Total future minimum lease payments, 2019	$ 5,687
Operating leases, Total future minimum lease payments, 2020	6,480
Operating leases, Total future minimum lease payments, 2021	5,822
Operating leases, Total future minimum lease payments, 2022	4,587
Operating leases, Total future minimum lease payments, 2023	3,299
Operating leases, Total future minimum lease payments, After 2023	6,945
Operating leases, Total future minimum lease payments	32,820
Operating leases, Less: interest	8,274
Operating leases, Present value of lease liabilities	24,546	$ 25,900
Finance leases
Finance leases, Total future minimum lease payments, 2019	806
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	1,444
Finance leases, Less: interest	24
Finance leases, Present value of lease liabilities	1,420
Total future minimum lease payments, 2019	6,493
Total future minimum lease payments, 2020	7,118
Total future minimum lease payments, 2021	5,822
Total future minimum lease payments, 2022	4,587
Total future minimum lease payments, 2023	3,299
Total future minimum lease payments, After 2023	6,945
Total future minimum lease payments	$ 34,264