Line of Credit Facility, Current Borrowing Capacity, Percent of Eligible Billed Accounts Receivable

No definition available.

Name:	cdi_LineofCreditFacilityCurrentBorrowingCapacityPercentofEligibleBilledAccountsReceivable
Namespace Prefix:	cdi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of Credit Facility, Current Borrowing Capacity, Percent of Eligible Unbilled Accounts Receivable Less Certain Reserves

+ References

No definition available.

+ Details

Name:	cdi_LineofCreditFacilityCurrentBorrowingCapacityPercentofEligibleUnbilledAccountsReceivableLessCertainReserves
Namespace Prefix:	cdi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of Credit Facility, Optional Additional Borrowing Capacity

+ References

No definition available.

+ Details

Name:	cdi_LineofCreditFacilityOptionalAdditionalBorrowingCapacity
Namespace Prefix:	cdi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

+ Details

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

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
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 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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 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

+ 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

+ Details

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

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_LineOfCreditFacilityAxis=exch_BAML
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cdi_CreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cdi_October2015LineofCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
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- Details

Name:	us-gaap_StatementGeographicalAxis=country_US
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- Details

Name:	us-gaap_StatementGeographicalAxis=country_CA
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Credit Facility (Details) - USD ($) $ in Millions	Oct. 30, 2015	Jun. 30, 2017	Dec. 31, 2016
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt instrument, term	5 years
BANK OF AMERICA - MERRILL LYNCH ATS [Member] \| Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Letters of credit outstanding		$ 3.3
Credit Agreement [Member] \| Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Borrowings outstanding		15.9
Credit Agreement [Member] \| BANK OF AMERICA - MERRILL LYNCH ATS [Member] \| Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Borrowings outstanding			$ 0.0
Letters of credit outstanding			3.3
Remaining borrowing capacity		$ 95.3	$ 122.3
October 2015 Line of Credit [Member] \| Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Current borrowing capacity	$ 150.0
Current borrowing capacity, percent of eligible unbilled accounts receivable less certain reserves	80.00%
Current borrowing capacity, percent of eligible billed accounts receivable	85.00%
Line of Credit Facility, Optional Additional Borrowing Capacity	$ 75.0
October 2015 Line of Credit [Member] \| Swingline Loans [Member]
Line of Credit Facility [Line Items]
Current borrowing capacity	25.0
October 2015 Line of Credit [Member] \| Letter of Credit [Member]
Line of Credit Facility [Line Items]
Current borrowing capacity	$ 15.0
Maximum [Member] \| Credit Agreement [Member] \| Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		4.25%
Maximum [Member] \| October 2015 Line of Credit [Member] \| Swingline Loans [Member]
Line of Credit Facility [Line Items]
Current borrowing capacity, percent of eligible unbilled accounts receivable less certain reserves	30.00%
Minimum [Member] \| Credit Agreement [Member] \| Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		2.33%
UNITED STATES \| October 2015 Line of Credit [Member] \| Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Current borrowing capacity	$ 135.0
CANADA \| October 2015 Line of Credit [Member] \| Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Current borrowing capacity	$ 15.0