Notes Payable (Details Textuals) (USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 30, 2011	Mar. 08, 2011
New Revolving Loan Facility [Member]
Notes Payable [Line Items]
Borrowing capacity under Revolving Loan Facility		$ 600.0
Borrowing rate under Revolving Loan Facility		138
Leverage ratio on restrictive financial covenants		35.00%
Contracutal interest rate on borrowing under the Facility	1.61%
Commitment fees for Revolving Loan Facility	20.00%
Remaining borrowing capacity under Revolving Loan Facility as reduced by outstanding letters of credit	492.1
Old Revolving Loan Facility [Member]
Notes Payable [Line Items]
Borrowing capacity under Revolving Loan Facility		$ 575.0
Senior Notes [Member]
Notes Payable [Line Items]
Percentage of senior notes	6.30%

Basis points

Name:	hcc_BasisPoints
Namespace Prefix:	hcc
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Borrowing Rate under Revolving Loan Facility

+ Details

Name:	hcc_BorrowingRate
Namespace Prefix:	hcc
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Contracutal interest rate on borrowing under the Facility.

+ Details

Name:	hcc_ContracutalInterestRateOnBorrowingUnderFacility
Namespace Prefix:	hcc
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Notes Payabel [Line Items]

+ Details

Name:	hcc_NotesPayableLineItems
Namespace Prefix:	hcc
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Interest rate stated in the contractual debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

Reference 2: 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(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ Details

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Namespace Prefix:	us-gaap
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 129
-Paragraph 2, 4
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 22
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 22
-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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