Leases and Right of Use Assets - Supplemental Balance Sheet Information (Details) $ in Thousands	Jun. 30, 2019 USD ($)
Operating leases:
Operating leases - right of use assets	$ 13,574
Current operating lease obligations	7,578
Non-current operating leases	6,037
Total operating lease liabilities	13,615
Finance leases:
Property, plant and equipment, at cost	102,074
Accumulated amortization	(21,913)
Property, plant and equipment, net	80,161
Current finance lease obligations	21,665
Long-term finance lease obligations	59,012
Total lease obligations	$ 80,677
Weighted average remaining lease term:
Operating leases	42 months
Finance leases	45 months
Weighted average discount rate:
Operating leases	3.87%
Finance leases	3.41%