Variable Interest Entities Balance Sheet (Details) - Variable Interest Entity, Primary Beneficiary [Member] $ in Thousands	Sep. 30, 2018 USD ($)
ASSETS
Total Assets	$ 878,051
Liabilities:
Total Liabilities	494,796
Cash [Member]
ASSETS
Current assets	950
Receivables - Related Party [Member]
ASSETS
Current assets	15,053
Receivables Excluding Third Party [Member]
ASSETS
Current assets	7,185
Other Current Assets [Member]
ASSETS
Current assets	2,623
Property, Plant and Equipment [Member]
ASSETS
Non-current assets	848,836
Other Noncurrent Assets [Member]
ASSETS
Non-current assets	3,404
Accounts Payable [Member]
Liabilities:
Current liabilities	53,391
Accounts Payable - Related Party [Member]
Liabilities:
Current liabilities	4,427
Revolving Credit Facility [Member]
Liabilities:
Current liabilities	44,000
Long-term Debt [Member]
Liabilities:
Non-current liabilities	$ 392,978