Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
Sep. 30, 2017	Dec. 31, 2016
Commitments and Contingencies [Abstract]
Equipment purchases commitments	$ 0.2	$ 0.6

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