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Subsequent Events (Details) - Senior secured term loan facility | Apr. 03, 2018 | Mar. 31, 2018
--- | --- | ---
Subsequent Event [Line Items] |  |
Net leverage ratio |  | 2.49
Subsequent Event |  |
Subsequent Event [Line Items] |  |
Margin on borrowings, reduced interest rate from refinancing in bps | 0.25% |
ABR |  |
Subsequent Event [Line Items] |  |
Variable interest rate margin |  | 1.00%
ABR | Subsequent Event |  |
Subsequent Event [Line Items] |  |
Variable interest rate margin | 0.75% |
LIBOR |  |
Subsequent Event [Line Items] |  |
Margin on borrowings, reduced interest rate from refinancing in bps |  | 0.25%
Variable interest rate margin |  | 2.00%
LIBOR | Subsequent Event |  |
Subsequent Event [Line Items] |  |
Variable interest rate margin | 1.75% |
Maximum | Subsequent Event |  |
Subsequent Event [Line Items] |  |
Net leverage ratio | 3.75 |

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- Definition Margin on Borrowings, Reduced Interest Rate from Refinancing in bps + References No definition available. + Details
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Namespace Prefix: | cdw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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- Definition Net Leverage Ratio + References No definition available. + Details
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- Definition Variable Interest Rate Margin + References No definition available. + Details
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Namespace Prefix: | cdw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References No definition available. + Details
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- Details
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- Details
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- Details
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Namespace Prefix: |
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Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
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Balance Type: |
Period Type: |

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- Details
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