XML 45 R33.htm IDEA: XBRL DOCUMENT
v3.21.1

Unaudited Condensed Consolidated Financial Statements (Narrative) (Details) | 3 Months Ended
--- | ---
Mar. 31, 2021
Statement of Financial Position [Abstract] |
Plan of Reorganization, Support of Revolving Credit Facility, Percentage | 100.00%

X
- References No definition available. + Details
Name: | us-gaap_StatementOfFinancialPositionAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Plan of Reorganization, Support of Revolving Credit Facility, Percentage + References No definition available. + Details
Name: | val_PlanOfReorganizationSupportOfRevolvingCreditFacilityPercentage
Namespace Prefix: | val_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration