Amount of gain (loss) on sale or disposal of property, plant and equipment assets, including oil and gas property and timber property.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

+ Details

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

- Definition

An amount representing an agreement for an unconditional promise by the maker to pay the Entity (holder) a definite sum of money at a future date(s) more than one year from the balance sheet date. Such amount may include accrued interest receivable in accordance with the terms of the debt. The debt also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. This amount does not include amounts related to receivables held-for-sale.

+ 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 210.5-02.17)

-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:	debit
Period Type:	instant

- Definition

Cash received for the sale of real estate that is not part of an investing activity during the current period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3179-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The deferred gain on the sale of property to be recognized as payments on the note receivable are received

+ References

No definition available.

+ Details

Name:	usak_DeferredGainSaleOfProperty
Namespace Prefix:	usak_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Balloon payment due at maturity of the note receivable

+ References

No definition available.

+ Details

Name:	usak_MaturitiesOfNoteReceivable
Namespace Prefix:	usak_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Annual rate of interest on the note receivable.

+ References

No definition available.

+ Details

Name:	usak_NoteReceivableInterestRate
Namespace Prefix:	usak_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Note 2 - Note Receivable (Details Textual) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
Note 2 - Note Receivable (Details Textual) - USD ($)	Nov. 30, 2010	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Proceeds from Sale of Real Estate	$ 200,000
Notes, Loans and Financing Receivable, Gross, Noncurrent	$ 2,100,000
Note Receivable Interest Rate	7.00%
Maturities Of Note Receivable	$ 1,900,000
Deferred Gain Sale Of Property	$ 700,000
Gain (Loss) on Disposition of Property Plant Equipment		$ 2,100	$ 2,000	$ 6,200	$ 5,800