Commitments and Contingencies Narrative (Details) $ in Thousands	3 Months Ended
Mar. 31, 2018 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Contractual price	$ 1,304
Purchase commitment, period	5 years

Period covered by the long-term purchase commitment, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	us-gaap_LongtermPurchaseCommitmentPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration