The initial applicable margin percentage points added to the debt instrument.

No definition available.

Name:	unfi_DebtInstrumentInitialApplicableMargin
Namespace Prefix:	unfi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the percentage of eligible accounts receivable maintain under the amended and restated credit facility.

+ References

No definition available.

+ Details

Name:	unfi_LineOfCreditFacilityAvailabilityOfBorrowingCapacitySubjectToPercentageOfEligibleAccountsReceivable
Namespace Prefix:	unfi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the percentage of net orderly liquidation value of eligible inventory subject to customary reserves maintain under the amended and restated credit facility.

+ References

No definition available.

+ Details

Name:	unfi_LineOfCreditFacilityAvailabilityOfBorrowingCapacitySubjectToPercentageOfNetOrderlyLiquidationValueOfEligibleInventory
Namespace Prefix:	unfi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Increase in maximum borrowing capacity under the credit facility if any one or more of the existing banks or new banks agree to provide such increased commitment amount.

+ References

No definition available.

+ Details

Name:	unfi_LineOfCreditFacilityContingentIncreaseToMaximumBorrowingCapacity
Namespace Prefix:	unfi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of incremental increase required to maximum borrowing capacity under the credit facility if any one or more of the existing banks or new banks agree to provide an increase to the commitment amount.

+ References

No definition available.

+ Details

Name:	unfi_LineOfCreditFacilityContingentIncreaseToMaximumBorrowingCapacityAmountOfRequiredIncrement
Namespace Prefix:	unfi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the amount paid to the counterparty to terminate the interest rate derivative

+ References

No definition available.

+ Details

Name:	unfi_PaymentsForInterestRateDerivativeTerminationCosts
Namespace Prefix:	unfi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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

- Definition

Decrease for amounts repaid on the credit facility for the period.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 4

-Section 08

-Paragraph f

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(f))

-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

+ Details

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

- Definition

Increase for additional borrowings on the credit facility during the period.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityIncreaseAdditionalBorrowings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

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

- Details

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

SUBSEQUENT EVENTS (Details) (Debt refinancing, USD $) In Millions, unless otherwise specified	1 Months Ended
	May 31, 2012	May 24, 2012
U.S. Borrowers
SUBSEQUENT EVENTS
Maximum borrowing base		$ 450.0
UNFI Canada
SUBSEQUENT EVENTS
Maximum borrowing base		50.0
Prior Credit Agreement
SUBSEQUENT EVENTS
Maximum borrowing base		400.0
Repayment of existing indebtedness	174.1
Amended and Restated Credit Facility
SUBSEQUENT EVENTS
Maximum borrowing base		500.0
Borrowings on line of credit facility to repay indebtedness	217.7
Percentage of eligible accounts receivable		90.00%
Percentage of net orderly liquidation value of eligible inventory		85.00%
Amended and Restated Credit Facility \| Minimum
SUBSEQUENT EVENTS
Contingent increase to borrowing capacity, required incremental increase		10.0
Amended and Restated Credit Facility \| Maximum
SUBSEQUENT EVENTS
Contingent increase to borrowing capacity		100.0
Amended and Restated Credit Facility \| U.S. Borrowers \| Federal funds rate
SUBSEQUENT EVENTS
Reference rate	federal funds rate
Spread on reference rate (as a percent)		0.50%
Amended and Restated Credit Facility \| U.S. Borrowers \| One-month LIBOR
SUBSEQUENT EVENTS
Reference rate	one-month LIBOR
Spread on reference rate (as a percent)		1.00%
Amended and Restated Credit Facility \| UNFI Canada \| Reuters Canadian Deposit Offering Rate
SUBSEQUENT EVENTS
Reference rate	30-day Reuters Canadian Deposit Offering Rate
Spread on reference rate (as a percent)		0.50%
Amended and Restated Credit Facility \| UNFI Canada \| Prime rate of Bank of America N.A.'s Canada branch
SUBSEQUENT EVENTS
Reference rate	Bankers' acceptance equivalent rate for a one-month interest period
Spread on reference rate (as a percent)		1.00%
Amended and Restated Credit Facility \| UNFI Canada \| Annual rates applicable to Canadian Dollar bankers' acceptances
SUBSEQUENT EVENTS
Reference rate	annual rates applicable to Canadian Dollar bankers' acceptances
Spread on reference rate (as a percent)		0.50%
Amended and Restated Credit Facility \| UNFI Canada \| Base rate and prime rate
SUBSEQUENT EVENTS
Reference rate	Base rate and Prime rate
Initial applicable margin		0.50%
Amended and Restated Credit Facility \| UNFI Canada \| LIBOR and Canadian Dollar bankers' acceptances-rate loans
SUBSEQUENT EVENTS
Reference rate	LIBOR and Canadian Dollar bankers' acceptances rates
Initial applicable margin		1.50%
Letter of credit
SUBSEQUENT EVENTS
Maximum borrowing base		40.0
Short-term swingline borrowings
SUBSEQUENT EVENTS
Maximum borrowing base		35.0
Term loan
SUBSEQUENT EVENTS
Repayment of existing indebtedness	43.6
Amount paid to terminate interest rate swap	$ 0.3