Warranty Obligations - Additional Information (Details) $ in Millions	Dec. 31, 2017 USD ($)
BFP and BPT [Member]
Business Acquisition [Line Items]
Warranty liability subject to recovery	$ 4

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration