LIBOR contract rate lock in period.

No definition available.

Name:	csgs_LiborContractRateLockInPeriod
Namespace Prefix:	csgs_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum amount of unrestricted cash and cash equivalents and unused availability under the 2012 Revolver that CSG must have, if the 2010 Convertible Notes are still outstanding.

+ References

No definition available.

+ Details

Name:	csgs_MinimumCashAndUnusedCapacityUnderRevolverWhichAllowsForEarlyTerminationOfTwoThousandTwelveCreditAgreement
Namespace Prefix:	csgs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The average effective interest rate during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 3: 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(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateDuringPeriod
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- 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

Date the credit facility terminates, in CCYY-MM-DD format.

+ 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 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3255-108585

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfLongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 15

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

+ Details

Name:	us-gaap_RepaymentsOfLongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_LongtermDebtTypeAxis=csgs_TermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Debt - 2012 Credit Agreement (Details Textual) (USD $)	12 Months Ended
Debt - 2012 Credit Agreement (Details Textual) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Proceeds from issuance of debt			$ 150,000,000
Minimum amount of combined unrestricted cash and cash equivalents and unused availability under the 2012 Revolver that provides for early termination of 2012 Credit Agreement	200,000,000
Cash used for repayment of debt	15,000,000us-gaap_RepaymentsOfLongTermDebt	15,000,000us-gaap_RepaymentsOfLongTermDebt	190,000,000us-gaap_RepaymentsOfLongTermDebt
Term Loan
Debt Instrument [Line Items]
Credit agreement period	5 years
Proceeds from issuance of debt			150,000,000
Revolving Loan
Debt Instrument [Line Items]
Credit agreement period	5 years
Credit Agreement
Debt Instrument [Line Items]
Credit Agreement			250,000,000
Credit Agreement \| Term Loan
Debt Instrument [Line Items]
Credit Agreement			150,000,000
Credit Agreement \| Revolving Loan
Debt Instrument [Line Items]
Credit Agreement			100,000,000
2012 Credit Agreement
Debt Instrument [Line Items]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.375%
2012 Credit agreement early termination date	Dec. 01, 2016
Cash used for repayment of debt		15,000,000
2012 Credit Agreement \| Minimum
Debt Instrument [Line Items]
Basis spread on term loan	2.00%
LIBOR contract rate lock in period	1 month
2012 Credit Agreement \| Maximum
Debt Instrument [Line Items]
Basis spread on term loan	2.75%
LIBOR contract rate lock in period	6 months
2012 Credit Agreement \| Term Loan
Debt Instrument [Line Items]
Basis spread on term loan	2.00%
Term loan combined interest rate	2.25%
2012 Credit agreement early termination date	Dec. 01, 2016
2012 Credit Agreement \| Term Loan 2012 \| Minimum
Debt Instrument [Line Items]
Basis spread on term loan	1.00%
2012 Credit Agreement \| Term Loan 2012 \| Maximum
Debt Instrument [Line Items]
Basis spread on term loan	1.75%
2012 Credit Agreement \| Revolving Loan
Debt Instrument [Line Items]
Credit Agreement	$ 100,000,000	$ 100,000,000
2012 Credit agreement early termination date	Dec. 01, 2016