Revenue (Narrative) (Details) - Maximum [Member]	6 Months Ended
Jun. 30, 2018
Disaggregation Of Revenue [Line Items]
Payment terms on sales	45 days
Incremental costs to fulfill customer arrangements amortization period	1 year

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