Commitments and Contingencies - Pipeline Capacity Agreements (Details) - Pipeline capacity agreements $ in Thousands	Mar. 31, 2018 USD ($)
Future minimum throughput payments
2019	$ 50,201
2020	41,379
Total	$ 91,580

Amount of contractual obligation due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

No definition available.

Name:	us-gaap_ContractualObligationDueInNextTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant