Credit agreement amendment date.

No definition available.

Name:	usap_CreditAgreementAmendmentDate
Namespace Prefix:	usap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instruments libor option rate (excluding swing loan).

+ References

No definition available.

+ Details

Name:	usap_DebtInstrumentsLiborOptionRateExcludingSwingLoan
Namespace Prefix:	usap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Original line of credit expiration (was extended to 03/2017).

+ References

No definition available.

+ Details

Name:	usap_LineOfCreditFacilityExpiration
Namespace Prefix:	usap_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of credit facility extended expiration year.

+ References

No definition available.

+ Details

Name:	usap_LineOfCreditFacilityExtendedExpirationYear
Namespace Prefix:	usap_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum leverage ratio.

+ References

No definition available.

+ Details

Name:	usap_MaximumLeverageRatio
Namespace Prefix:	usap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum swing loans available under revolving credit facility.

+ References

No definition available.

+ Details

Name:	usap_MaximumSwingLoansAvailableUnderRevolvingCreditFacility
Namespace Prefix:	usap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Minimum fixed charge coverage ratio.

+ References

No definition available.

+ Details

Name:	usap_MinimumFixedChargeCoverageRatio
Namespace Prefix:	usap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The minimum amount which can be requested to increase the capacity of the revolver.

+ References

No definition available.

+ Details

Name:	usap_MinimumIncrementalIncreaseInRevolverCapacity
Namespace Prefix:	usap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The Company may prepay any outstanding convertible notes, in whole or in part, after August 17, 2014 during a fiscal quarter if the Company's share price is greater than 140% of the current conversion price for at least twenty of the trading days in the thirty consecutive trading day period ending on the last trading day of the immediately preceding quarter.

+ References

No definition available.

+ Details

Name:	usap_SpecifiedPrepaymentDateOfConvertibleNotesOutstanding
Namespace Prefix:	usap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of a written promise to pay a note, initially due after one year or beyond the operating cycle if longer, which can be exchanged for a specified amount of one or more securities (typically common stock), at the option of the issuer or the holder.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

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

Reference 2: 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(a))

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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20, 22

-Article 5

+ Details

Name:	us-gaap_ConvertibleNotesPayable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The price per share of the conversion feature embedded in the debt instrument.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 20

-Section 50

-Paragraph 5

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6928298&loc=SL6031898-161870

+ Details

Name:	us-gaap_DebtInstrumentConvertibleConversionPrice1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Minimum percentage of common stock price to conversion price of convertible debt instruments to determine eligibility of conversion.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the 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

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

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

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ 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)(2))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments applied to principal.

+ 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)

-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:	duration

- Definition

For an unclassified balance sheet, the carrying amount (net of accumulated amortization) as of the balance sheet date of capitalized costs associated with the issuance of debt instruments (for example, legal, accounting, underwriting, printing, and registration costs) that will be charged against earnings over the life of the debt instruments to which such costs pertain.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28555-108399

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 210.5-02.17)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 17

-Article 5

+ Details

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

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ 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 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

+ Details

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

- 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

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	instant

Long-Term Debt - Additional Information (Detail) (USD $)	6 Months Ended		1 Months Ended		6 Months Ended				6 Months Ended
	Jun. 30, 2013	Dec. 18, 2011	Aug. 31, 2011 Before Amendment	Aug. 31, 2011 After Amendment	Jun. 30, 2013 Revolving Credit Facility	Jun. 30, 2013 Revolving Credit Facility Minimum	Jun. 30, 2013 Revolving Credit Facility Maximum	Aug. 18, 2011 Convertible Promissory Notes	Jun. 30, 2013 Term Loan	Jun. 30, 2013 Amended Credit Agreement	Jun. 30, 2012 Amended Credit Agreement	Mar. 19, 2012 Amended Credit Agreement Revolving Credit Facility	Mar. 19, 2012 Amended Credit Agreement Term Loan
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity												$ 105,000,000	$ 20,000,000
Deferred financing costs										487,000	348,000
Line of credit original expiration date	2016-08
Line of credit facility extended expiration year	2017-03
Credit agreement amendment date	Mar. 19, 2012
Minimum incremental increase in revolver capacity						10,000,000
Maximum borrowings under revolver							130,000,000
Commitment fee on the daily unused portion of the Revolver					0.25%
Maximum swing loans available under revolving credit facility	7,000,000
Quarterly term loan payments									750,000
Variable LIBOR rate										2.20%
Maximum leverage ratio	375.00%		375.00%	275.00%
Minimum fixed charge coverage ratio	110.00%		110.00%	120.00%
Convertible notes								$ 20,000,000
Interest rate on convertible notes		4.00%
Maturity date of Convertible Notes	Aug. 17, 2017
Commencement of prepay period of convertible notes outstanding	Aug. 17, 2014
Conversion stock price for Convertible Notes	$ 47.1675
Stock price trigger for convertible note prepay option	140.00%