XML 89 R69.htm IDEA: XBRL DOCUMENT v3.22.0.1

Debt (Schedule Of Long-Term Debt Instruments) (Details) - USD ($) $ in Millions	3 Months Ended		4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2012	Apr. 30, 2021	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2018	Dec. 31, 2016	Dec. 31, 2015	Mar. 31, 2018
Debt Instrument [Line Items]
Long-term Debt			$ 544.8
Liabilities Subject to Compromise			0.0	$ 0.0	$ 0.0	$ 7,313.7
Current maturities of long-term debt				0.0	0.0	0.0
Long-term Debt, Excluding Current Maturities				545.3	545.3	0.0
Backstop Commitment Fees			$ 0.0	0.0		447.9
Letters of Credit Outstanding, Amount				$ 36.5	$ 36.5
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount						$ 27.0
6.875% Senior notes due 2020
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				6.875%	6.875%
6.875% Senior notes due 2020 | Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	6.875%
Senior Note Maturity Year	2020
4.70% Senior notes due 2021
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				4.70%	4.70%
4.70% Senior notes due 2021 | Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage		4.70%
Senior Note Maturity Year		2021
4.875%SeniorNotesDue2022Member [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				4.875%	4.875%
4.875%SeniorNotesDue2022Member [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				4.875%	4.875%
3.00% Exchangeable senior notes due 2024
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				3.00%	3.00%
4.50% Senior notes due 2024
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				4.50%	4.50%
4.50% Senior notes due 2024 | Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage									4.50%
Senior Note Maturity Year									2024
4.75%SeniorNotesDue2024Member [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				4.75%	4.75%
4.75%SeniorNotesDue2024Member [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				4.75%	4.75%
8.00% Senior notes due 2024
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				8.00%	8.00%
8.00% Senior notes due 2024 | Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage							8.00%
Senior Note Maturity Year							2024
5.20% Senior notes due 2025
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				5.20%	5.20%
5.20% Senior notes due 2025 | Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage								5.20%
Senior Note Maturity Year								2025
7.38%SeniorNotesDue2025 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				7.375%	7.375%
7.38%SeniorNotesDue2025 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				7.375%	7.375%
7.75% Senior notes due 2026
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				7.75%	7.75%
7.75% Senior notes due 2026 | Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage										7.75%
7.20% Senior notes due 2027
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				7.20%	7.20%
7.20% Senior notes due 2027 | Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage						7.20%
7.875% Senior notes due 2040
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				7.875%	7.875%
5.40%SeniorNotesDue2042 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				5.40%	5.40%
5.75% Senior notes due 2044
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				5.75%	5.75%
5.75% Senior notes due 2044 | Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage								5.75%	5.75%
Senior Note Maturity Year								2044	2044
5.85%SeniorNotesDue2044 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				5.85%	5.85%
5.85%SeniorNotesDue2044 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				5.85%	5.85%
Three percent exchangeable senior notes due twenty twenty four [Member]
Debt Instrument [Line Items]
Backstop Commitment Fees					$ 128.8
Debt Instrument, Unamortized Discount				$ 119.5	119.5
Debt Issuance Costs, Net				9.3	9.3
Reported Value Measurement [Member]
Debt Instrument [Line Items]
Long-term Debt				545.3	545.3	$ 7,096.3
Liabilities Subject to Compromise				0.0	0.0	7,096.3
Long-term Debt, Excluding Current Maturities				545.3	545.3	0.0
Reported Value Measurement [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Liabilities Subject to Compromise						6,500.0
Reported Value Measurement [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Long-term Debt				0.0	0.0	581.0
Reported Value Measurement [Member] | 6.875% Senior notes due 2020 | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt				0.0	0.0	122.9
Reported Value Measurement [Member] | 4.70% Senior notes due 2021 | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt				0.0	0.0	100.7
Reported Value Measurement [Member] | 4.875%SeniorNotesDue2022Member [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt				0.0	0.0	620.8
Reported Value Measurement [Member] | 3.00% Exchangeable senior notes due 2024 | Convertible Debt [Member]
Debt Instrument [Line Items]
Long-term Debt				0.0	0.0	849.5
Reported Value Measurement [Member] | 4.50% Senior notes due 2024 | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt				0.0	0.0	303.4
Reported Value Measurement [Member] | 4.75%SeniorNotesDue2024Member [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt				0.0	0.0	318.6
Reported Value Measurement [Member] | 8.00% Senior notes due 2024 | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt				0.0	0.0	292.3
Reported Value Measurement [Member] | 5.20% Senior notes due 2025 | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt				0.0	0.0	333.7
Reported Value Measurement [Member] | 7.38%SeniorNotesDue2025 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt				0.0	0.0	360.8
Reported Value Measurement [Member] | 7.75% Senior notes due 2026 | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt				0.0	0.0	1,000.0
Reported Value Measurement [Member] | 7.20% Senior notes due 2027 | Debentures Due 2027
Debt Instrument [Line Items]
Long-term Debt				0.0	0.0	112.1
Reported Value Measurement [Member] | 7.875% Senior notes due 2040 | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt				0.0	0.0	300.0
Reported Value Measurement [Member] | 5.40%SeniorNotesDue2042 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt				0.0	0.0	400.0
Reported Value Measurement [Member] | 5.75% Senior notes due 2044 | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt				0.0	0.0	1,000.5
Reported Value Measurement [Member] | 5.85%SeniorNotesDue2044 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt				$ 0.0	$ 0.0	400.0
Reported Value Measurement [Member] | Line of Credit [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Long-term Debt						581.0
Reported Value Measurement [Member] | Three percent exchangeable senior notes due twenty twenty four [Member] | Convertible Debt [Member]
Debt Instrument [Line Items]
Long-term Debt						$ 849.5

X

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

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.

+ References

No definition available.

+ Details

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

X

- Definition

Amount, after accumulated amortization, of debt discount.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=124435984&loc=d3e28541-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1D
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495340-112611

+ Details

Name:	us-gaap_DebtInstrumentUnamortizedDiscount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of write-off of debt issuance costs and debt discounts related to prepetition debt obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 55
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84165509&loc=d3e56145-112766

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 45
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=124437977&loc=d3e55730-112764

+ Details

Name:	us-gaap_DebtorReorganizationItemsWriteOffOfDeferredFinancingCostsAndDebtDiscounts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1D
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495340-112611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=124435984&loc=d3e28555-108399

+ Details

Name:	us-gaap_DeferredFinanceCostsNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Total amount of liabilities subject to compromise.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=124433192&loc=d3e56015-112765

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 55
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84165509&loc=d3e56145-112766

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=84165509&loc=d3e56426-112766

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=124437977&loc=d3e55717-112764

+ Details

Name:	us-gaap_LiabilitiesSubjectToCompromise
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=123466204&loc=SL6031897-161870

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69C
-URI http://asc.fasb.org/extlink&oid=123466577&loc=SL123495737-112612

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69B
-URI http://asc.fasb.org/extlink&oid=123466577&loc=SL123495735-112612

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1D
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495340-112611

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19,20)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebtCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebtNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Senior Note Maturity Year

+ References

No definition available.

+ Details

Name:	val_SeniorNoteMaturityYear
Namespace Prefix:	val_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=val_SixPointEightSevenFivePercentSeniorNotesDueTwoThousandTwentyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=val_FourPointSevenZeroPercentSeniorNotesDueTwoThousandTwentyOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=val_A4.875SeniorNotesDue2022MemberMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=val_ThreePercentExchangeableSeniorNotesDueTwoThousandTwentyFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=val_FourPointFivePercentSeniorNotesMemberMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=val_A4.75SeniorNotesDue2024MemberMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=val_A8.00seniornotesdue2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=val_FivePointTwoPercentSeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=val_A7.38SeniorNotesDue2025Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=val_SevenPointSevenFivePercentSeniorNotesDueTwoThousandTwentySixMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=val_SevenPointTwoZeroPercentDebenturesDueTwoThousandTwentySevenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=val_SevenPointEightSevenFivePercentSeniorNotesDueTwoThousandFortyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=val_A5.40SeniorNotesDue2042Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=val_FivePointSevenFivePercentSeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=val_A5.85SeniorNotesDue2044Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=val_ThreepercentexchangeableseniornotesduetwentytwentyfourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_ConvertibleDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=val_DebenturesDue2027Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: