The amount of the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4332-108586

+ Details

Name:	us-gaap_DebtConversionOriginalDebtAmount1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of long-term debt and capital lease obligation due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-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=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 6

-Section H

+ Details

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

- Definition

Aggregate carrying amount, as of the balance sheet date, of current assets not separately disclosed in the balance sheet. Current assets are expected to be realized or consumed within one year (or the normal operating cycle, if longer).

+ References

+ Details

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

- Definition

Aggregate carrying amount, as of the balance sheet date, of noncurrent assets not separately disclosed in the balance sheet. Noncurrent assets are expected to be realized or consumed after one year (or the normal operating cycle, if longer).

+ References

+ Details

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

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

- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

+ Details

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

- Definition

Interest due under Restructuring Agreement

+ References

No definition available.

+ Details

Name:	wlt_InterestdueunderRestructuringAgreement
Namespace Prefix:	wlt_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_ScenarioPreviouslyReportedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_NewAccountingPronouncementEarlyAdoptionAxis=us-gaap_NewAccountingPronouncementEarlyAdoptionEffectMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wlt_SeniorSecuredNotes9.50PercentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	wlt_EarlyAdoptionLineItemEffectAxis=wlt_DebtissuancecostothercurrentassetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	wlt_EarlyAdoptionLineItemEffectAxis=wlt_DebtissuancecostotherlongtermassetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	wlt_EarlyAdoptionLineItemEffectAxis=wlt_DebtissuancecostlongtermdebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Business and Basis of Presentation (Details) - USD ($) $ in Thousands	Aug. 26, 2015	Sep. 30, 2015	Jul. 15, 2015	Dec. 31, 2014
Revision of Loss on Extinguishment of Debt
Interest due under Restructuring Agreement (as a percent)			80.00%
Debt Conversion, Original Debt, Amount	$ 1,900,000
Other current assets		$ 2,458		$ 9,285
Revision of debt issuance costs		(46,086)		(54,765)
Other long-term assets		89,963		67,748
Long-term debt		$ 0		3,068,878
Prior to revision
Revision of Loss on Extinguishment of Debt
Other current assets				19,542
Other long-term assets				112,256
Long-term debt				3,123,643
New Accounting Pronouncement, Early Adoption, Effect
Revision of Loss on Extinguishment of Debt
Other current assets				9,285
Other long-term assets				67,748
Long-term debt				3,068,878
9.50% senior secured notes
Revision of Loss on Extinguishment of Debt
Weighted average stated interest rate (as a percent)		9.50%	9.50%
Revision of debt issuance costs		$ (15,400)		(17,800)
Debt issuance cost, other current assets \| New Accounting Pronouncement, Early Adoption, Effect
Revision of Loss on Extinguishment of Debt
Revision of debt issuance costs				(10,257)
Debt issuance cost, other long term assets \| New Accounting Pronouncement, Early Adoption, Effect
Revision of Loss on Extinguishment of Debt
Revision of debt issuance costs				(44,508)
Debt issuance cost, long term debt \| New Accounting Pronouncement, Early Adoption, Effect
Revision of Loss on Extinguishment of Debt
Revision of debt issuance costs				$ (54,765)