Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.13,16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_DebtAndCapitalLeaseObligations
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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.

+ Details

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

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ Details

Name:	us-gaap_LongTermDebtFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the maximum amount of borrowings available under the credit agreement.

+ Details

Name:	wlt_DebtInstrumentMaximumBorrowingsAvailableUnderCreditAgreement
Namespace Prefix:	wlt
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Fair Value of Financial Instruments (Details 2) (USD $)	Sep. 30, 2011	Dec. 31, 2010	Apr. 02, 2011 2011 Credit Agreement	Sep. 30, 2011 2011 term loan A	Sep. 30, 2011 2011 term loan B
Debt
Debt, carried at cost	$ 2,424,739,000	$ 168,473,000		$ 935,000,000	$ 1,396,500,000
Estimated fair value				911,600,000	1,346,000,000
Maximum amount of borrowings available under the credit agreement			$ 2,725,000,000