LEASES - Reconciliation of future undiscounted cash flows to the operating and finance lease liabilities, and the related ROU assets (Details) $ in Thousands	Mar. 31, 2020 USD ($)
Operating leases
2020 (excluding the six months ended March 31, 2020)	$ 2,667
2021	4,696
2022	4,036
2023	3,090
2024 and thereafter	6,931
Total minimum lease payments	21,420
Less: amounts representing interest	2,202
Present value of net minimum lease payments	19,218
Less: Current portion of lease obligations	4,208
Non-current portion of lease obligations	15,010
ROU assets	18,901
Finance leases
2020 (excluding the six months ended March 31, 2020)	1,455
2021	2,930
2022	3,011
2023	3,094
2024 and thereafter	31,481
Total minimum lease payments	41,971
Less: amounts representing interest	10,821
Present value of net minimum lease payments	31,150
Less: Current portion of lease obligations	1,902
Non-current portion of lease obligations	29,248
ROU assets	$ 28,072
Location of operating lease liabilities included on Consolidated Balance Sheets	us-gaap:OtherAccruedLiabilitiesCurrent us-gaap:OperatingLeaseLiabilityNoncurrent
Location of finance lease liabilities included on Consolidated Balance Sheets	us-gaap:OtherAccruedLiabilitiesCurrent us-gaap:OtherLiabilitiesNoncurrent
Location of operating lease ROU assets included on Consolidated Balance Sheets	us-gaap:OperatingLeaseRightOfUseAsset
Location of finance lease ROU assets included on Consolidated Balance Sheets	us-gaap:PropertyPlantAndEquipmentNet