v2.4.0.8

Subsequent Events (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013
Subsequent Events [Abstract]
Accounts receivable	$ 5,475
Inventory	9,023
Prepaid expenses	1,328
Net PP&E	81,501
Deferred charges and other assets	168
Current maturities of long-term debt	(48)
Trade account payable and taxes payable	(14,268)
Long-term debt	(1,088)
Deferred income taxes	$ (15,121)

X

- Definition

Deferred Income Taxes Held For Sale

+ References

No definition available.

+ Details

Name:	musa_DeferredIncomeTaxesHeldForSale
Namespace Prefix:	musa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Long Term Debt, Current, Held For Sale

+ References

No definition available.

+ Details

Name:	musa_LongTermDebtCurrentHeldForSale
Namespace Prefix:	musa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Long Term Debt, Noncurrent, Held For Sale

+ References

No definition available.

+ Details

Name:	musa_LongTermDebtNoncurrentHeldForSale
Namespace Prefix:	musa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Prepaid Expenses Held For Sale

+ References

No definition available.

+ Details

Name:	musa_PrepaidExpensesHeldForSale
Namespace Prefix:	musa_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Trade Accounts And Taxes Payable Held For Sale

+ References

No definition available.

+ Details

Name:	musa_TradeAccountsAndTaxesPayableHeldForSale
Namespace Prefix:	musa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Property, plant and equipment that is held for sale apart from normal operations and anticipated to be sold in less than one year.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 45

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e1107-107759

+ Details

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

X

- Definition

Carrying amount as of the balance sheet date of inventories classified as held for sale that are segregated from normal operations and that are anticipated to be sold within one year (or in the operating cycle if longer).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1436-107760

+ Details

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

X

- Definition

The lower of the carrying value or fair value less cost to sell of current assets held for sale that are not elsewhere specified in the taxonomy. The carrying value of major classes of assets and liabilities of the disposal group are separately disclosed in the balance sheet in the specific concepts provided.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 45

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e1107-107759



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 35

-Paragraph 43

-URI http://asc.fasb.org/extlink&oid=29634951&loc=d3e1739-110224

+ Details

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

X

- Definition

The aggregate of (trade) accounts and loans receivables that will be sold to other entities, at lower of cost or net realizable value.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522

+ Details

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

X

- Details

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