Cash And Cash Equivalents And Investments In Marketable Securities (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended
Sep. 30, 2011 Boe years
Cash And Cash Equivalents And Investments In Marketable Securities [Abstract]
Shares of Connacher Oil and Gas Limited held	1,000,000
Maximum term to maturity from date of purchase (years)	2
Marketable debt securities	$ 370
Sale and maturities of marketable debt securities	$ 194.4

Cash and Cash Equivalents and Investments in Marketable Securities.

Name:	hoc_CashAndCashEquivalentsAndInvestmentsInMarketableSecuritiesAbstract
Namespace Prefix:	hoc
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Marketable Securities, Debt Maturities, Maximum Maturity Term

+ Details

Name:	hoc_MarketableSecuritiesDebtMaturitiesMaximumMaturityTerm
Namespace Prefix:	hoc
Data Type:	xbrli:positiveIntegerItemType
Balance Type:	na
Period Type:	duration

- Definition

Balance held at close of period in number of shares.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 12C

-Paragraph Column B

-Article 12

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 12

-Paragraph Column B

-Article 12

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 14

-Paragraph Column B

-Article 12

+ Details

Name:	us-gaap_InvestmentOwnedBalanceShares
Namespace Prefix:	us-gaap
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

For an unclassified balance sheet, this item represents investments in debt securities having predetermined or determinable maturity dates.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Subparagraph a

-Article 7

+ Details

Name:	us-gaap_MarketableSecuritiesFixedMaturities
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cash inflow associated with the aggregate amount received by the entity through sale or maturity of marketable securities (trading, held-to-maturity, or available-for-sale) during the period.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 15

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 16

-Subparagraph b

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 16

-Subparagraph a

+ Details

Name:	us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration