v2.4.0.8

Income Taxes (Narrative) (Details) (USD $) In Thousands, unless otherwise specified | 12 Months Ended |
--- | --- | ---
Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
Income Taxes [Line Items] |  |  |
Federal and state net operating losses acquired in business combinations | $ 6,547 |  |
Valuation allowance additions in the tax provision | 1,301 | 2,093 |
Valuation allowance reductions | 1,362 | 2,289 |
Potential benefits included in reserve that would impact effective tax rate | 3,274 | 4,095 |
Liabilities included in the reserve |  | 3,775 |
Tax benefit recognized due to decrease in accrued interest | 310 | 170 |
Interest accrued, net of federal benefit | $ 623 | $ 933 | $ 1,157
Minimum [Member] |  |  |
Income Taxes [Line Items] |  |  |
Federal Net Operating Losses Expire Period | 2020 |  |
State Net Operating Losses Expire Period | 2014 |  |
Maximum [Member] |  |  |
Income Taxes [Line Items] |  |  |
Federal Net Operating Losses Expire Period | 2032 |  |
State Net Operating Losses Expire Period | 2034 |  |

X
- Definition Federal net operating losses expire period. + References No definition available. + Details
Name: | cnc_FederalNetOperatingLossesExpirePeriod
Namespace Prefix: | cnc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | cnc_IncomeTaxesLineItems
Namespace Prefix: | cnc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Net Operating Losses Acquired In Business Combinations + References No definition available. + Details
Name: | cnc_NetOperatingLossesAcquiredInBusinessCombinations
Namespace Prefix: | cnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition State net operating losses expire period. + References No definition available. + Details
Name: | cnc_StateNetOperatingLossesExpirePeriod
Namespace Prefix: | cnc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tax Benefit Recognized Due to Decrease in Accrued Interest + References No definition available. + Details
Name: | cnc_TaxBenefitRecognizedDueToDecreaseInAccruedInterest
Namespace Prefix: | cnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Unrecognized Tax benefit, Liabilities Included + References No definition available. + Details
Name: | cnc_UnrecognizedTaxBenefitLiabilitiesIncluded
Namespace Prefix: | cnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Valuation allowance additions. + References No definition available. + Details
Name: | cnc_ValuationAllowanceAdditions
Namespace Prefix: | cnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Valuation allowance reductions. + References No definition available. + Details
Name: | cnc_ValuationAllowanceReductions
Namespace Prefix: | cnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of interest expense accrued for an underpayment of income taxes. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319 + Details
Name: | us-gaap_UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319 + Details
Name: | us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant