Employee Stock Benefit Plans - Positions Eliminated (Details)	Jan. 30, 2018 employee
Workforce Reduction
Number of employees eliminated	60

The number of positions eliminated during the period as a result of restructuring activities.

No definition available.

Name:	us-gaap_RestructuringAndRelatedCostNumberOfPositionsEliminated
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration