Employee Benefits (Detail Textuals) (USD $) In Millions, unless otherwise specified	9 Months Ended	3 Months Ended
Sep. 28, 2013	Jun. 29, 2013 Hourly Pension Plan	Sep. 28, 2013 Hourly Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Deferred and amortized period for defined benefit plan contribution	5 years
Total defined benefit employer minimum required contribution related to the 2012 plan year	$ 3.2
Cash contribution made in three quarters of 2013	0.8
Defined benefit employer minimum required contribution for the 2012 plan year not made in 2012	2.1
Independent appraisals cost of land and buildings located in Charleston, S.C. and Buffalo, N.Y.		6.8
Lease back period for real property		20 years
Lease back period extension option for real property		5 years
Rent payments recorded as contributions by hourly pension plan			$ 0.3

Represents the deferred and amortized period for required defined benefit contribution.

No definition available.

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Data Type:	xbrli:durationItemType
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Period Type:	duration

Represents cash contribution to pension plan required to be made in three quarters of year fiscal 2013.

No definition available.

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

Represents defined benefit employer minimum required contribution for the 2012 plan year not made in 2012.

No definition available.

Name:	bxc_DefinedBenefitEmployerMinimumRequiredContributionForTwoThousandTwelvePlanYearNotMadeInTwoThousandTwelve
Namespace Prefix:	bxc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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Total defined benefit plan employer minimum required contribution related to the 2012 plan year.

No definition available.

Name:	bxc_DefinedBenefitEmployerMinimumRequiredContributionRelatedToTwoThousandTwelvePlanYear
Namespace Prefix:	bxc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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Represents the lease back period extension option for real property.

No definition available.

Name:	bxc_LeaseBackPeriodExtensionOptionsForRealProperty
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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the lease back period for real property.

No definition available.

Name:	bxc_LeaseBackPeriodForRealProperty
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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents real property valued by independent appraisals.

No definition available.

Name:	bxc_RealPropertyValuedByIndependentAppraisals
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Rental payments made on leased properties, which serve as contributions to our hourly pension plan.

No definition available.

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

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