XML 45 R34.htm IDEA: XBRL DOCUMENT
v3.19.1

Short-term and Long-term Investments, Restricted Deposits - Narrative (Details) | 3 Months Ended
--- | ---
Mar. 31, 2019 position
Schedule Of Investments And Restricted Deposits By Type [Line Items] |
Positions from which gross unrealized losses were generated | 1,966
Total unrealized investment positions | 4,339
Commercial mortgage-backed securities |
Schedule Of Investments And Restricted Deposits By Type [Line Items] |
Investments recorded at fair value that carry rating of AA Plus, weighted average (in years) | 3 years 9 months
Rated Securities | External Credit Rating, Investment Grade |
Schedule Of Investments And Restricted Deposits By Type [Line Items] |
Percentage of investments in rated securities carry an investment grade rating by nationally recognized statistical rating organizations | 97.00%

X
- Definition Investments Recorded At Fair Value That Carry Rating Of A A Plus, Weighted Average, Duration + References No definition available. + Details
Name: | cnc_InvestmentsRecordedAtFairValueThatCarryRatingOfAAPlusWeightedAverageDuration
Namespace Prefix: | cnc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Positions from which gross unrealized losses were generated + References No definition available. + Details
Name: | cnc_PositionsFromWhichGrossUnrealizedLossesWereGenerated
Namespace Prefix: | cnc_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Total Unrealized Investment Positions + References No definition available. + Details
Name: | cnc_TotalUnrealizedInvestmentPositions
Namespace Prefix: | cnc_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13531-108611 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13537-108611 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592 + Details
Name: | us-gaap_ConcentrationRiskPercentage1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- 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_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CommercialMortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByBenchmarkAxis=cnc_RatedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ExternalCreditRatingByGroupingAxis=us-gaap_ExternalCreditRatingInvestmentGradeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |