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Commitments and Contingencies (Details) | Dec. 30, 2017 employee
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Commitments and Contingencies Disclosure [Abstract] |
Number of persons employed on full-time basis | 1,500
Percentages of employees represented by various labor unions | 34.00%
Percentage of collective bargaining agreements up for renewal in 2016 | 11.00%

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- Definition Represents number of collective bargaining agreements up for renewal in One Year + References No definition available. + Details
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Namespace Prefix: | bxc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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- Definition Percentage of employees represented by various labor unions. + References No definition available. + Details
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Namespace Prefix: | bxc_
Data Type: | num:percentItemType
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- Definition Number of persons employed by the Entity + References No definition available. + Details
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Namespace Prefix: | dei_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

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- References No definition available. + Details
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Namespace Prefix: | us-gaap_
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