Commitments and Contingencies (Narrative) (Details) $ in Millions	6 Months Ended
Jun. 30, 2018 USD ($)
Commitments and Contingencies [Abstract]
Equipment purchases commitments	$ 1.8

The minimum amount the entity agreed to spend under the long-term purchase commitment.

No definition available.

Name:	us-gaap_LongTermPurchaseCommitmentAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration