Fair Value Measurement (Narrative) (Details) - USD ($)	3 Months Ended	12 Months Ended
Jan. 27, 2017	Jan. 29, 2016	Oct. 28, 2016
Fair Value Disclosures [Abstract]
Fair value hierarchy, transfers amount	$ 0	$ 0	$ 0

Amount of transfers of assets or liabilities measured on a recurring basis between levels of the fair value hierarchy.

No definition available.

Name:	val_FairValueHierarchyTransfersAmount
Namespace Prefix:	val_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration