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Financial Instruments (Bonds) - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2017 | Dec. 31, 2016
Investments Debt And Equity Securities [Abstract] |  |
Corporate and municipal bonds | $ 49.5 | $ 42.4
Maturity dates of bonds, start date | 2018-01 |
Maturity dates of bonds, end date | 2023-12 |

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- Definition Corporate and municipal bonds net book value. + References No definition available. + Details
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- Definition Maturity date of bond end date. + References No definition available. + Details
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Balance Type: | na
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- Definition Maturity date of bond start date. + References No definition available. + Details
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Namespace Prefix: | cbz_
Data Type: | xbrli:gYearMonthItemType
Balance Type: | na
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- References No definition available. + Details
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