v2.4.0.8

Fair Value Measurements (Fair Value Measurements By Level For Assets Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified | Dec. 31, 2013 | Dec. 31, 2012
--- | --- | ---
Cash and cash equivalents | $ 974,304 | $ 745,933
U.S. Treasury securities and obligations of U.S. government corporations and agencies | 224,423 | 97,360
Corporate securities | 296,086 | 295,111
Municipal securities, General obligation | 54,422 | 86,571
Municipal securities, Pre-refunded | 10,917 | 5,422
Municipal securities, Revenue | 69,054 | 84,064
Municipal securities, Variable rate demand notes | 28,575 | 23,385
Asset backed securities | 139,050 | 74,637
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure | 33,891 | 0
Total investments | 856,418 | 666,550
Cash and cash equivalents | 26,642 | 14,455
Certificates of deposit | 5,891 | 5,890
U.S. Treasury securities and obligations of U.S. government corporations and agencies | 14,413 | 13,941
Total restricted deposits | 46,946 | 34,286
Interest rate swap contract | 9,576 | 16,304
Total assets at fair value | 1,887,244 | 1,463,073
Level I [Member] |  |
Cash and cash equivalents | 974,304 | 745,933
U.S. Treasury securities and obligations of U.S. government corporations and agencies | 212,185 | 57,114
Corporate securities | 0 | 0
Municipal securities, General obligation | 0 | 0
Municipal securities, Pre-refunded | 0 | 0
Municipal securities, Revenue | 0 | 0
Municipal securities, Variable rate demand notes | 0 | 0
Asset backed securities | 0 | 0
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure | 0 | 0
Total investments | 212,185 | 57,114
Cash and cash equivalents | 26,642 | 14,455
Certificates of deposit | 5,891 | 5,890
U.S. Treasury securities and obligations of U.S. government corporations and agencies | 14,413 | 13,941
Total restricted deposits | 46,946 | 34,286
Interest rate swap contract | 0 | 0
Total assets at fair value | 1,233,435 | 837,333
Level II [Member] |  |
Cash and cash equivalents | 0 | 0
U.S. Treasury securities and obligations of U.S. government corporations and agencies | 12,238 | 40,246
Corporate securities | 296,086 | 295,111
Municipal securities, General obligation | 54,422 | 86,571
Municipal securities, Pre-refunded | 10,917 | 5,422
Municipal securities, Revenue | 69,054 | 84,064
Municipal securities, Variable rate demand notes | 28,575 | 23,385
Asset backed securities | 139,050 | 74,637
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure | 33,891 | 0
Total investments | 644,233 | 609,436
Cash and cash equivalents | 0 | 0
Certificates of deposit | 0 | 0
U.S. Treasury securities and obligations of U.S. government corporations and agencies | 0 | 0
Total restricted deposits | 0 | 0
Interest rate swap contract | 9,576 | 16,304
Total assets at fair value | 653,809 | 625,740
Level III [Member] |  |
Cash and cash equivalents | 0 | 0
U.S. Treasury securities and obligations of U.S. government corporations and agencies | 0 | 0
Corporate securities | 0 | 0
Municipal securities, General obligation | 0 | 0
Municipal securities, Pre-refunded | 0 | 0
Municipal securities, Revenue | 0 | 0
Municipal securities, Variable rate demand notes | 0 | 0
Asset backed securities | 0 | 0
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure | 0 | 0
Total investments | 0 | 0
Cash and cash equivalents | 0 | 0
Certificates of deposit | 0 | 0
U.S. Treasury securities and obligations of U.S. government corporations and agencies | 0 | 0
Total restricted deposits | 0 | 0
Interest rate swap contract | 0 | 0
Total assets at fair value | $ 0 | $ 0

X
- Definition This element represents asset backed securities reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This element represents restricted cash and cash equivalents reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + References No definition available. + Details
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Namespace Prefix: | cnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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X
- Definition This element represents restricted certificates of deposit reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
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- Definition Corporate securities + References No definition available. + Details
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- Definition This element represents general obligation municipal securities reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
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- Definition Pre Refunded Municipal Securities Fair Value Disclosure + References No definition available. + Details
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Namespace Prefix: | cnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Definition This element represents revenue municipal securities reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + References No definition available. + Details
Name: | cnc_RevenueMunicipalSecuritiesFairValueDisclosure
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- Definition This element represents total restricted deposits reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + References No definition available. + Details
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- Definition This element represents U.S. Treasury securities and obligations of U.S. government corporations and agencies reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + References No definition available. + Details
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- Definition This element represents restricted U.S. Treasury securities and obligations of U.S. government corporations and agencies reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
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- Definition This element represents variable rate demand note municipal securities reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + References No definition available. + Details
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- Definition Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258 + Details
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- Definition Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Cash -URI http://asc.fasb.org/extlink&oid=6506951 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Cash Equivalents -URI http://asc.fasb.org/extlink&oid=6507016 + Details
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- Definition Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13433-108611 + Details
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- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Available-for-Sale Securities -URI http://asc.fasb.org/extlink&oid=6505594 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Subparagraph a, f, g -Article 7 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 35 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=27723805&loc=d3e24584-111560 + Details
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- Definition Fair value of securitized, pay-through debt securities collateralized by real estate mortgage loans classified as available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Mortgage-Backed Securities -URI http://asc.fasb.org/extlink&oid=6517959 + Details
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