Line of credit accordion credit facility.

No definition available.

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Namespace Prefix:	bxc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line of Credit Facility, Covenant Restriction, Coverage Ratio, Fixed Amount

+ References

No definition available.

+ Details

Name:	bxc_LineofCreditFacilityCovenantRestrictionCoverageRatioFixedAmount
Namespace Prefix:	bxc_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Line of Credit Facility, Minimum Percentage of Maximum Borrowing Capacity or Alternative Base, Before Covered Ratio is Applicable

+ References

No definition available.

+ Details

Name:	bxc_LineofCreditFacilityMinimumPercentageofMaximumBorrowingCapacityorAlternativeBaseBeforeCoveredRatioisApplicable
Namespace Prefix:	bxc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of Credit Facility, Minimum Remaining Borrowing Capacity

+ References

No definition available.

+ Details

Name:	bxc_LineofCreditFacilityMinimumRemainingBorrowingCapacity
Namespace Prefix:	bxc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of Credit Facility, Minimum Remaining Borrowing Capacity Level Before Covered Ratio is Applicable

+ References

No definition available.

+ Details

Name:	bxc_LineofCreditFacilityMinimumRemainingBorrowingCapacityLevelBeforeCoveredRatioisApplicable
Namespace Prefix:	bxc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line of Credit Facility, Minimum Remaining Borrowing Capacity Level Before Covered Ratio is Applicable While Concurrent Debt is Outstanding

+ References

No definition available.

+ Details

Name:	bxc_LineofCreditFacilityMinimumRemainingBorrowingCapacityLevelBeforeCoveredRatioisApplicableWhileConcurrentDebtisOutstanding
Namespace Prefix:	bxc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line of Credit Facility, Revolving Credit Converted to Term Loan, Pursuant to Credit Agreement

+ References

No definition available.

+ Details

Name:	bxc_LineofCreditFacilityRevolvingCreditConvertedtoTermLoanPursuanttoCreditAgreement
Namespace Prefix:	bxc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of Credit, Future Required Principal Payment

+ References

No definition available.

+ Details

Name:	bxc_LineofCreditFutureRequiredPrincipalPayment
Namespace Prefix:	bxc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ 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)
-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 02
-Paragraph 19, 20, 22
-Article 5

+ Details

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

- 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

+ Details

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

- Definition

The effective interest rate at the end of the reporting period.

+ References

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
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

+ Details

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

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_DomesticLineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=bxc_WellsFargoBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=bxc_TrancheALoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=bxc_CibcAssetBasedLendingIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=country_CA
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=bxc_BluelinxBuildingProductsCanadaLtdMember
Namespace Prefix:
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Period Type:

Revolving Credit Facilities (Details)	12 Months Ended
Revolving Credit Facilities (Details)	Jan. 02, 2016 USD ($)	Mar. 24, 2016 USD ($)	Mar. 10, 2016 USD ($)	Aug. 04, 2006 USD ($)
Revolving credit facility \| US
Line of Credit Facility [Line Items]
Fixed charge coverage ratio	1.2
Minimum remaining borrowing capacity level before covered ratio is applicable, while Tranche A Loan is outstanding	$ 35,000,000.0
Minimum remaining borrowing capacity level before covered ratio is applicable	$ 39,000,000.0
Minimum percentage of maximum borrowing capacity or alternative base, before covered ratio is applicable	12.50%
Revolving credit facility \| Subsequent Event \| US
Line of Credit Facility [Line Items]
Minimum remaining excess capacity			$ 35,000,000.0
Wells Fargo Bank \| Revolving credit facility \| U.S.
Line of Credit Facility [Line Items]
Revolving credit facility maximum available credit	$ 467,500,000.0			$ 370,000,000.0
Line of credit accordion credit	75,000,000.0
Future required principal payment	35,000,000.0
Outstanding lines of credit	215,900,000
Revolving credit facility excess availability	$ 51,200,000
Interest rate on revolving credit facility	4.20%
Wells Fargo Bank \| Revolving credit facility \| U.S. \| Subsequent Event
Line of Credit Facility [Line Items]
Revolving credit facility maximum available credit		$ 370,000,000.0
Wells Fargo Bank \| Tranche A Loan \| U.S.
Line of Credit Facility [Line Items]
Line of credit facility, revolving credit converted to term loan, pursuant to credit agreement				$ 20,000,000.0
Wells Fargo Bank \| Tranche A Loan \| U.S. \| Subsequent Event
Line of Credit Facility [Line Items]
Future required principal payment		$ 6,000,000.0
Canadian Imperial Bank of Commerce \| Revolving credit facility \| Canada \| BlueLinx Canada
Line of Credit Facility [Line Items]
Revolving credit facility maximum available credit	$ 15,000,000.0
Line of credit accordion credit	5,000,000.0
Outstanding lines of credit	2,900,000
Revolving credit facility excess availability	$ 1,400,000
Interest rate on revolving credit facility	3.70%
Maximum available credit	$ 10,000,000.0