Commitments and Contingencies - Receivable Purchase Agreement (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Mar. 31, 2018
Commitments and Contingencies
Trade receivables from customers without recourse to be sold, maximum amount	$ 23.0	$ 23.0
Receivable Purchase Agreement, term	1 year
Trade receivables, sold		$ 0.0

The face amount of accounts receivable that will be sold to other entities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65884687&loc=d3e4428-111522

Name:	us-gaap_TradeReceivablesHeldForSaleAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant