Centene (CNC) 10-Q 22 Oct 13 2013 Q3 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	9 Months Ended
	Sep. 30, 2013	Oct. 11, 2013
Document And Entity Information [Abstract]
Entity Registrant Name	CENTENE CORP
Entity Central Index Key	1071739
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	30-Sep-13
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		54,768,884

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$741,281	$843,952
Premium and related receivables	355,947	263,452
Short-term investments	122,631	139,118
Other current assets	148,576	127,080
Total current assets	1,368,435	1,373,602
Long-term investments	816,910	614,723
Restricted deposits	40,911	34,793
Property, software and equipment, net	390,200	377,726
Goodwill	347,548	256,288
Intangible assets, net	50,541	20,268
Other long-term assets	124,492	64,282
Total assets	3,139,037	2,741,682
Current liabilities:
Medical claims liability	1,071,672	926,302
Premium deficiency reserve	0	41,475
Accounts payable and accrued expenses	270,381	191,343
Unearned revenue	41,873	34,597
Current portion of long-term debt	3,046	3,373
Total current liabilities	1,386,972	1,197,090
Long-term debt	517,931	535,481
Other long-term liabilities	49,043	55,344
Total liabilities	1,953,946	1,787,915
Commitments and contingencies
Stockholders' equity:
Common stock, $.001 par value; authorized 100,000,000 shares; 57,872,798 issued and 54,767,551 outstanding at September 30, 2013, and 55,339,160 issued and 52,329,248 outstanding at December 31, 2012	58	55
Additional paid-in capital	578,188	450,856
Accumulated other comprehensive income:
Unrealized (loss) gain on investments, net of tax	-1,845	5,189
Retained earnings	678,679	566,820
Treasury stock, at cost (3,105,247 and 3,009,912 shares, respectively)	-75,541	-69,864
Total Centene stockholders' equity	1,179,539	953,056
Noncontrolling interest	5,552	711
Total stockholders' equity	1,185,091	953,767
Total liabilities and stockholders' equity	$3,139,037	$2,741,682

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Stockholders' equity
Common stock, par value (in dollars per share)	$0.00	$0.00
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	57,872,798	55,339,160
Common stock, shares outstanding (in shares)	54,767,551	52,329,248
Treasury stock, at cost (in shares)	3,105,247	3,009,912

Consolidated_Statements_Of_Ope

Consolidated Statements Of Operations (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues:
Premium	$2,621,651	$2,184,061	$7,659,418	$5,853,469
Service	112,497	28,403	251,290	84,062
Premium and service revenues	2,734,148	2,212,464	7,910,708	5,937,531
Premium tax	69,504	235,657	264,781	333,484
Total revenues	2,803,652	2,448,121	8,175,489	6,271,015
Expenses:
Medical costs	2,298,881	2,036,999	6,810,892	5,370,080
Cost of services	100,479	21,744	218,844	66,897
General and administrative expenses	253,608	181,073	694,204	512,322
Premium tax expense	68,453	235,946	262,188	333,872
Impairment loss	0	0	0	28,033
Total operating expenses	2,721,421	2,475,762	7,986,128	6,311,204
Earnings (loss) from operations	82,231	-27,641	189,361	-40,189
Other income (expense):
Investment and other income	4,946	23,244	13,703	32,580
Interest expense	-6,603	-4,855	-20,261	-14,393
Earnings (loss) before income tax expense (benefit)	80,574	-9,252	182,803	-22,002
Income tax expense (benefit)	31,660	-9,547	71,967	-6,068
Net earnings (loss)	48,914	295	110,836	-15,934
Noncontrolling interest	-459	-3,524	-1,023	-8,732
Net earnings (loss) attributable to Centene Corporation	$49,373	$3,819	$111,859	($7,202)
Basic earnings (loss) per common share (in dollars per share)	$0.90	$0.07	$2.08	($0.14)
Diluted earnings (loss) per common share (in dollars per share)	$0.87	$0.07	$2	($0.14)
Weighted Average Number of Common Shares Outstanding
Basic (in shares)	54,679,660	51,584,860	53,863,779	51,393,345
Diluted (in shares)	56,933,056	53,806,197	55,956,421	51,393,345

Consolidated_Statement_Of_Comp

Consolidated Statement Of Comprehensive Earnings (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Other Comprehensive Income [Abstract]
Net earnings (loss)	$48,914	$295	$110,836	($15,934)
Reclassification adjustment, net of tax	-94	-1,023	-621	-1,495
Change in unrealized (loss) gain on investments, net of tax	2,310	1,883	-6,413	2,436
Other comprehensive earnings (loss)	2,216	860	-7,034	941
Comprehensive earnings (loss)	51,130	1,155	103,802	-14,993
Comprehensive earnings (loss) attributable to noncontrolling interest	-459	-3,524	-1,023	-8,732
Comprehensive earnings (loss) attributable to Centene Corporation	$51,589	$4,679	$104,825	($6,261)

Consolidated_Statement_Of_Stoc

Consolidated Statement Of Stockholders' Equity (USD $)	Total	Centene Stockholders' Equity - Common Stock [Member]	Centene Stockholders' Equity - Additional Paid-In Capital [Member]	Centene Stockholders' Equity - Accumulated Other Comprehensive Income (Loss) [Member]	Centene Stockholders' Equity - Retained Earnings [Member]	Centene Stockholders' Equity - Treasury Stock [Member]	Non Controlling Interest [Member]
In Thousands, except Share data, unless otherwise specified
Balance at Dec. 31, 2012	$953,767	$55	$450,856	$5,189	$566,820	($69,864)	$711
Balance (in shares) at Dec. 31, 2012	52,329,248	55,339,160				3,009,912
Comprehensive Earnings:
Net earnings (loss)	110,836				111,859		-1,023
Change in unrealized investment (loss) gain, net of $(3,999) tax	-7,034			-7,034
Comprehensive earnings (loss)	103,802
Common stock issued for acquisition	75,425	2	75,423
Common stock issued for acquisition (in shares)	1,716,690	1,716,690
Common stock issued for stock offering	15,225	0	15,225
Common stock issued for stock offering (in shares)	342,640	342,640
Common stock issued for employee benefit plans	8,285	1	8,284
Common stock issued for employee benefit plans (in shares)		474,308
Common stock repurchases	-5,677					-5,677
Common stock repurchases (in shares)						95,335
Stock compensation expense	27,252		27,252
Excess tax benefits from stock compensation	1,148		1,148
Contribution from noncontrolling interest	5,864						5,864
Balance at Sep. 30, 2013	$1,185,091	$58	$578,188	($1,845)	$678,679	($75,541)	$5,552
Balance (in shares) at Sep. 30, 2013	54,767,551	57,872,798				3,105,247

Consolidated_Statement_Of_Stoc1

Consolidated Statement Of Stockholders' Equity (Parenthetical) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013
Consolidated Statement of Stockholders' Equity (Parenthetical) [Abstract]
Tax on unrealized investment (loss) gain	($3,999)

Consolidated_Statements_Of_Cas

Consolidated Statements Of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net earnings (loss)	$110,836	($15,934)
Adjustments to reconcile net earnings (loss) to net cash provided by (used in) operating activities
Depreciation and amortization	50,220	49,892
Stock compensation expense	27,252	18,417
Impairment loss	0	28,033
Gain (Loss) on Sale of Notes Receivable	0	17,880
Deferred income taxes	1,626	-19,318
Changes in assets and liabilities
Premium and related receivables	-58,587	-139,414
Other current assets	-19,133	-23,487
Other assets	-65,397	1,918
Medical claims liabilites	103,895	374,046
Unearned revenue	7,976	122,077
Accounts payable and accrued expenses	48,840	-59,872
Other operating activities	4,142	-11,196
Net cash provided by (used in) operating activities	211,670	307,282
Cash flows from investing activities:
Capital expenditures	-46,383	-70,601
Purchases of investments	-666,016	-501,958
Sales and maturities of investments	451,034	434,009
Investments in acquisitions, net of cash acquired	-62,773	0
Net cash used in investing activities	-324,138	-138,550
Cash flows from financing activities:
Proceeds from exercise of stock options	7,674	11,686
Proceeds from borrowings	30,000	215,000
Payment of long-term debt	-40,842	-177,422
Proceeds from stock offering	15,225	0
Excess tax benefits from stock compensation	1,140	6,049
Common stock repurchases	-5,677	-2,154
Contribution from noncontrolling interest	5,864	1,032
Debt issue costs	-3,587	0
Net cash provided by financing activities	9,797	54,191
Net decrease in cash and cash equivalents	-102,671	222,923
Cash and cash equivalents, beginning of period	843,952	573,698
Cash and cash equivalents, end of period	741,281	796,621
Supplemental disclosures of cash flow information:
Interest paid	16,738	12,127
Income taxes paid	40,921	34,001
Equity issued in connection with acquisition	$75,425	$0

Basis_Of_Presentation

Basis Of Presentation	9 Months Ended
	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis Of Presentation	Basis of Presentation
	The accompanying interim financial statements have been prepared under the presumption that users of the interim financial information have either read or have access to the audited financial statements included in the Form 10-K for the fiscal year ended December 31, 2012.  The unaudited interim financial statements herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission.  Accordingly, footnote disclosures which would substantially duplicate the disclosures contained in the December 31, 2012 audited financial statements have been omitted from these interim financial statements where appropriate.  In the opinion of management, these financial statements reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair presentation of the results of the interim periods presented.
	Certain 2012 amounts in the notes to the consolidated financial statements have been reclassified to conform to the 2013 presentation. These reclassifications have no effect on net earnings or stockholders’ equity as previously reported.

Acquisition_Notes

Acquisition (Notes)	9 Months Ended
	Sep. 30, 2013
Acquisition [Abstract]
Acquisition	Acquisition: AcariaHealth, Inc.
	In April 2013, the Company acquired 100% of AcariaHealth, Inc., a specialty pharmacy company, for $142,495 in total consideration. The transaction consideration was financed through a combination of $75,425 of Centene common stock and $67,070 of cash on hand. The Company subsequently sold 342,640 shares of common stock for $15,225 related to funding the escrow account for the acquisition.
	The Company's allocation of fair value resulted in goodwill of $91,260 and other identifiable intangible assets of $35,000. The goodwill is not deductible for income tax purposes. The acquisition is recorded in the Specialty Services segment.

ShortTerm_And_LongTerm_Investm

Short-Term And Long-Term Investments And Restricted Deposits	9 Months Ended
	Sep. 30, 2013
Investments, Debt and Equity Securities [Abstract]
Short-Term And Long-Term Investments And Restricted Deposits	Short-term and Long-term Investments and Restricted Deposits
	Short-term and long-term investments and restricted deposits by investment type consist of the following:
		September 30, 2013										December 31, 2012
		Amortized			Gross		Gross			Fair		Amortized			Gross		Gross			Fair
		Cost			Unrealized		Unrealized Losses			Value		Cost			Unrealized		Unrealized Losses			Value
					Gains										Gains
	U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	247,051		$	308	$	(6,196	)	$	241,163	$	117,434		$	594	$	(221	)	$	117,807
	Corporate securities	327,083			3,115		(650		)	329,548		315,807			5,101		(198		)	320,710
	Restricted certificates of deposit	5,891			—		—			5,891		5,890			—		—			5,890
	Restricted cash equivalents	22,608			—		—			22,608		14,460			—		—			14,460
	Municipal securities:
	General obligation	61,101			544		(169		)	61,476		88,690			1,173		(26		)	89,837
	Pre-refunded	14,329			164		(1		)	14,492		5,337			85		—			5,422
	Revenue	76,753			534		(538		)	76,749		84,726			1,331		(30		)	86,027
	Variable rate demand notes	65,955			—		—			65,955		37,685			—		—			37,685
	Asset backed securities	128,343			656		(256		)	128,743		83,295			1,197		(17		)	84,475
	Cost and equity method investments	18,538			—		—			18,538		11,298			—		—			11,298
	Life insurance contracts	15,289			—		—			15,289		15,023			—		—			15,023
	Total	$	982,941		$	5,321	$	(7,810	)	$	980,452	$	779,645		$	9,481	$	(492	)	$	788,634
	The Company’s investments are classified as available-for-sale with the exception of life insurance contracts and certain cost and equity method investments.  The Company’s investment policies are designed to provide liquidity, preserve capital and maximize total return on invested assets with the focus on high credit quality securities.  The Company limits the size of investment in any single issuer other than U.S. treasury securities and obligations of U.S. government corporations and agencies.  As of September 30, 2013, 47% of the Company’s investments in securities recorded at fair value that carry a rating by S&P or Moody’s were rated AAA/Aaa, 66% were rated AA-/Aa3 or higher, and 94% were rated A-/A3 or higher.  At September 30, 2013, the Company held certificates of deposit, life insurance contracts and cost and equity method investments which did not carry a credit rating.
	The fair value of available-for-sale investments with gross unrealized losses by investment type and length of time that individual securities have been in a continuous unrealized loss position were as follows:
		September 30, 2013										December 31, 2012
		Less Than 12 Months					12 Months or More					Less Than 12 Months					12 Months or More
		Unrealized Losses			Fair		Unrealized Losses			Fair		Unrealized Losses			Fair		Unrealized Losses			Fair
					Value					Value					Value					Value
	U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	(6,196	)	$	196,888	$	—		$	—	$	(219	)	$	56,033	$	(2	)	$	202
	Corporate securities	(641		)	79,753		(9		)	42		(198		)	44,758		—			—
	Municipal securities:
	General obligation	(119		)	9,264		(50		)	2,453		(26		)	8,464		—			—
	Pre-refunded	(1		)	489		—			—		—			—		—			—
	Revenue	(531		)	28,866		(7		)	1,807		(30		)	3,325		—			—
	Asset backed securities	(256		)	35,140		—			—		(17		)	9,321		—			—
	Total	$	(7,744	)	$	350,400	$	(66	)	$	4,302	$	(490	)	$	121,901	$	(2	)	$	202
	As of September 30, 2013, the gross unrealized losses were generated from 89 positions out of a total of 356 positions.  The decline in fair value of fixed income securities is a result of movement in interest rates subsequent to the purchase of the security.
	For each security in an unrealized loss position, the Company assesses whether it intends to sell the security or if it is more likely than not the Company will be required to sell the security before recovery of the amortized cost basis for reasons such as liquidity, contractual or regulatory purposes.  If the security meets this criterion, the decline in fair value is other-than-temporary and is recorded in earnings.  The Company does not intend to sell these securities prior to maturity and it is not likely that the Company will be required to sell these securities prior to maturity; therefore, there is no indication of other than temporary impairment for these securities.
	The contractual maturities of short-term and long-term investments and restricted deposits are as follows:
		September 30, 2013										December 31, 2012
		Investments					Restricted Deposits					Investments					Restricted Deposits
		Amortized			Fair		Amortized			Fair		Amortized			Fair		Amortized			Fair
		Cost			Value		Cost			Value		Cost			Value		Cost			Value
	One year or less	$	121,753		$	122,631	$	36,600		$	36,606	$	138,011		$	139,118	$	34,403		$	34,435
	One year through five years	588,145			589,585		4,302			4,305		474,068			481,381		358			358
	Five years through ten years	169,250			164,201		—			—		94,006			93,878		—			—
	Greater than ten years	62,891			63,124		—			—		38,799			39,464		—			—
	Total	$	942,039		$	939,541	$	40,902		$	40,911	$	744,884		$	753,841	$	34,761		$	34,793
	Actual maturities may differ from contractual maturities due to call or prepayment options.  Asset backed securities are included in the one year through five years category, while cost and equity method investments and life insurance contracts are included in the five years through ten years category.  The Company has an option to redeem at amortized cost substantially all of the securities included in the greater than ten years category listed above.
	The Company continuously monitors investments for other-than-temporary impairment.  Certain investments have experienced a decline in fair value due to changes in credit quality, market interest rates and/or general economic conditions.  The Company recognizes an impairment loss for cost and equity method investments when evidence demonstrates that it is other-than-temporarily impaired.  Evidence of a loss in value that is other-than-temporary may include the absence of an ability to recover the carrying amount of the investment or the inability of the investee to sustain a level of earnings that would justify the carrying amount of the investment.
	Investment amortization of $7,612 and $8,676 was recorded in the nine months ended September 30, 2013 and 2012, respectively.

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements
	Assets and liabilities recorded at fair value in the consolidated balance sheets are categorized based upon the extent to which the fair value estimates are based upon observable or unobservable inputs.  Level inputs are as follows:
	Level Input:		Input Definition:
	Level I		Inputs are unadjusted, quoted prices for identical assets or liabilities in active markets at the measurement date.
	Level II		Inputs other than quoted prices included in Level I that are observable for the asset or liability through corroboration with market data at the measurement date.
	Level III		Unobservable inputs that reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date.
	The following table summarizes fair value measurements by level at September 30, 2013, for assets and liabilities measured at fair value on a recurring basis:
		Level I		Level II		Level III		Total
	Assets
	Cash and cash equivalents	$	741,281	$	—	$	—	$	741,281
	Investments available for sale:
	U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	213,772	$	14,979	$	—	$	228,751
	Corporate securities	—		329,548		—		329,548
	Municipal securities:
	General obligation	—		61,476		—		61,476
	Pre-refunded	—		14,492		—		14,492
	Revenue	—		76,749		—		76,749
	Variable rate demand notes	—		65,955		—		65,955
	Asset backed securities	—		128,743		—		128,743
	Total investments	$	213,772	$	691,942	$	—	$	905,714
	Restricted deposits available for sale:
	Cash and cash equivalents	$	22,608	$	—	$	—	$	22,608
	Certificates of deposit	5,891		—		—		5,891
	U.S. Treasury securities and obligations of U.S. government corporations and agencies	12,412		—		—		12,412
	Total restricted deposits	$	40,911	$	—	$	—	$	40,911
	Other long-term assets: Interest rate swap contract	$	—	$	10,596	$	—	$	10,596
	Total assets at fair value	$	995,964	$	702,538	$	—	$	1,698,502
	The following table summarizes fair value measurements by level at December 31, 2012, for assets and liabilities measured at fair value on a recurring basis:
		Level I		Level II		Level III		Total
	Assets
	Cash and cash equivalents	$	843,952	$	—	$	—	$	843,952
	Investments available for sale:
	U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	57,114	$	46,250	$	—	$	103,364
	Corporate securities	—		320,710		—		320,710
	Municipal securities:
	General obligation	—		89,837		—		89,837
	Pre-refunded	—		5,422		—		5,422
	Revenue	—		86,027		—		86,027
	Variable rate demand notes	—		37,685		—		37,685
	Asset backed securities	—		84,475		—		84,475
	Total investments	$	57,114	$	670,406	$	—	$	727,520
	Restricted deposits available for sale:
	Cash and cash equivalents	$	14,460	$	—	$	—	$	14,460
	Certificates of deposit	5,890		—		—		5,890
	U.S. Treasury securities and obligations of U.S. government corporations and agencies	14,443		—		—		14,443
	Total restricted deposits	$	34,793	$	—	$	—	$	34,793
	Other long-term assets: Interest rate swap contract	$	—	$	16,304	$	—	$	16,304
	Total assets at fair value	$	935,859	$	686,710	$	—	$	1,622,569
	The Company periodically transfers U.S. Treasury securities and obligations of U.S. government corporations and agencies between Level I and Level II fair value measurements dependent upon the level of trading activity for the specific securities at the measurement date.  The Company’s policy regarding the timing of transfers between Level I and Level II is to measure and record the transfers at the end of the reporting period.  At September 30, 2013, there were $101 transfers from Level I to Level II and $26,571 of transfers from Level II to Level I.  The Company utilizes matrix pricing services to estimate fair value for securities which are not actively traded on the measurement date.  The Company designates these securities as Level II fair value measurements.  The aggregate carrying amount of the Company’s life insurance contracts and other non-majority owned investments, which approximates fair value, was $33,827 and $26,321 as of September 30, 2013 and December 31, 2012, respectively.

Debt

Debt	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]
Debt	Debt
	Debt consists of the following:
		September 30, 2013			December 31, 2012
	Senior notes, at par	$	425,000		$	425,000
	Unamortized premium on senior notes	6,495			7,823
	Interest rate swap fair value	10,596			16,304
	Senior notes	442,091			449,127
	Revolving credit agreement	—			—
	Mortgage notes payable	73,447			84,081
	Capital leases and other	5,439			5,646
	Total debt	520,977			538,854
	Less current portion	(3,046		)	(3,373		)
	Long-term debt	$	517,931		$	535,481
	Senior Notes
	In May 2011, the Company issued $250,000 non-callable 5.75% Senior Notes due June 1, 2017 (the $250,000 Notes) at a discount to yield 6%. In connection with the May 2011 issuance, the Company entered into an interest rate swap for a notional amount of $250,000. Gains and losses due to changes in the fair value of the interest rate swap completely offset changes in the fair value of the hedged portion of the underlying debt and are recorded as an adjustment to the $250,000 Notes. At September 30, 2013, the fair value of the interest rate swap increased the fair value of the notes by $10,596 and the variable interest rate of the swap was 3.76%.
	In November 2012, the Company issued an additional $175,000 non-callable 5.75% Senior Notes due June 1, 2017 ($175,000 Add-on Notes) at a premium to yield 4.29%. The indenture governing the $250,000 Notes and the $175,000 Add-on Notes contains non-financial and financial covenants, including requirements of a minimum fixed charge coverage ratio. Interest is paid semi-annually in June and December. At September 30, 2013, the total net unamortized debt premium on the $250,000 Notes and $175,000 Add-on Notes was $6,495.
	Revolving Credit Agreement
	In May 2013, the Company entered into a new unsecured $500,000 revolving credit facility and terminated its previous $350,000 revolving credit facility. Borrowings under the agreement bear interest based upon LIBOR rates, the Federal Funds Rate or the Prime Rate. The agreement has a maturity date of June 1, 2018, provided it will mature 90 days prior to the maturity date of the Company's 5.75% Senior Notes due 2017 if such notes are not refinanced (or extended) or certain financial conditions are not met, including carrying $100,000 of unrestricted cash on deposit. As of September 30, 2013, the Company had no borrowings outstanding under the agreement.
	The agreement contains non-financial and financial covenants, including requirements of minimum fixed charge coverage ratios, maximum debt-to-EBITDA ratios and minimum tangible net worth. The Company is required not to exceed a maximum debt-to-EBITDA ratio of 3.25 as of September 30, 2013 and 3.0 as of December 31, 2013 and thereafter. As of September 30, 2013, the Company's availability under the new revolving credit agreement would have been limited to approximately $400,000 as a result of the debt-to-EBITDA ratio.
	Mortgage Notes Payable
	The Company had a mortgage note of $8,700 at December 31, 2012 collateralized by an office building and parking garage. In June 2013, the Company paid the balance of this mortgage note.
	Letters of Credit
	The Company had outstanding letters of credit of $28,682 as of September 30, 2013, which were not part of the revolving credit facility.  The letters of credit bore interest at 0.52% as of September 30, 2013.

Stockholders_Equity_Notes

Stockholders' Equity (Notes)	9 Months Ended
	Sep. 30, 2013
Stockholders' Equity Attributable to Parent [Abstract]
Stockholders' Equity	Stockholders' Equity
	In April 2013, the Company completed the acquisition of AcariaHealth, Inc. and as a result, issued 1,716,690 shares of Centene common stock to the selling stockholders. Additionally, the Company filed an equity shelf registration statement related to funding the escrow account for the acquisition and sold 342,640 shares of Centene common stock for $15,225.

Earnings_Loss_Per_Share

Earnings (Loss) Per Share	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]
Earnings (Loss) Per Share	Earnings (Loss) Per Share
	The following table sets forth the calculation of basic and diluted net earnings per common share:
		Three Months Ended September 30,				Nine Months Ended September 30,
		2013		2012		2013		2012
	Net earnings (loss) attributable to Centene Corporation	$	49,373	$	3,819	$	111,859	$	(7,202	)
	Shares used in computing per share amounts:
	Weighted average number of common shares outstanding	54,679,660		51,584,860		53,863,779		51,393,345
	Common stock equivalents (as determined by applying the treasury stock method)	2,253,396		2,221,337		2,092,642		—
	Weighted average number of common shares and potential dilutive common shares outstanding	56,933,056		53,806,197		55,956,421		51,393,345
	Net earnings (loss) per share attributable to Centene Corporation:
	Basic earnings (loss) per common share	$	0.9	$	0.07	$	2.08	$	(0.14	)
	Diluted earnings (loss) per common share	$	0.87	$	0.07	$	2	$	(0.14	)
	The calculation of diluted earnings per common share for the three and nine months ended September 30, 2013 excludes the impact of 14,532 shares and 76,957 shares, respectively, related to anti-dilutive stock options, restricted stock and restricted stock units. The calculation of diluted earnings (loss) per common share for the three months ended September 30, 2012 excludes the impact of 44,642 shares related to anti-dilutive stock options, restricted stock and restricted stock units. The calculation for the nine months ended September 30, 2012 excludes the impact of 4,638,757 shares (before application of the treasury stock method) related to stock options, restricted stock and restricted stock units as the Company incurred losses during the period and the shares would be anti-dilutive.

Segment_Information

Segment Information	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]
Segment Information	Segment Information
	Centene operates in two segments: Medicaid Managed Care and Specialty Services.  The Medicaid Managed Care segment consists of Centene’s health plans including all of the functions needed to operate them.  The Specialty Services segment consists of Centene’s specialty companies offering auxiliary healthcare services and products. The health plan in Massachusetts, operated by our individual health insurance business, is included in the Specialty Services segment.
	In January 2013, the Company reclassified the health plan in Arizona, which is primarily a long-term care operation, to the Medicaid Managed Care segment. As a result, the financial results of the Arizona health plan have been reclassified from the Specialty Services segment to the Medicaid Managed Care segment for all periods presented.
	Segment information for the three months ended September 30, 2013, follows:
		Medicaid			Specialty		Eliminations			Consolidated
		Managed Care			Services					Total
	Premium and service revenues from external customers	$	2,510,221		$	223,927	$	—		$	2,734,148
	Premium and service revenues from internal customers	9,885			542,238		(552,123		)	—
	Total premium and service revenues	$	2,520,106		$	766,165	$	(552,123	)	$	2,734,148
	Earnings from operations	$	68,083		$	14,148	$	—		$	82,231
	Segment information for the three months ended September 30, 2012, follows:
		Medicaid			Specialty		Eliminations			Consolidated
		Managed Care			Services					Total
	Premium and service revenues from external customers	$	2,072,079		$	140,385	$	—		$	2,212,464
	Premium and service revenues from internal customers	25,138			442,388		(467,526		)	—
	Total premium and service revenues	$	2,097,217		$	582,773	$	(467,526	)	$	2,212,464
	Earnings (loss) from operations	$	(55,239	)	$	27,598	$	—		$	(27,641	)
	Segment information for the nine months ended September 30, 2013, follows:
		Medicaid			Specialty		Eliminations			Consolidated
		Managed Care			Services					Total
	Premium and service revenues from external customers	$	7,367,236		$	543,472	$	—		$	7,910,708
	Premium and service revenues from internal customers	31,050			1,660,639		(1,691,689		)	—
	Total premium and service revenues	$	7,398,286		$	2,204,111	$	(1,691,689	)	$	7,910,708
	Earnings from operations	$	116,609		$	72,752	$	—		$	189,361
	Segment information for the nine months ended September 30, 2012, follows:
		Medicaid			Specialty		Eliminations			Consolidated
		Managed Care			Services					Total
	Premium and service revenues from external customers	$	5,507,972		$	429,559	$	—		$	5,937,531
	Premium and service revenues from internal customers	62,751			1,206,293		(1,269,044		)	—
	Total premium and service revenues	$	5,570,723		$	1,635,852	$	(1,269,044	)	$	5,937,531
	Earnings (loss) from operations	$	(72,740	)	$	32,551	$	—		$	(40,189	)

Contingencies

Contingencies	9 Months Ended
	Sep. 30, 2013
Contingencies [Abstract]
Contingencies	Contingencies
	In October 2012, the Company notified the Kentucky Cabinet for Health and Family Services (Cabinet) that it was exercising a contractual right that it believes allows the Company to terminate its Medicaid Managed Care contract with the Commonwealth of Kentucky (Commonwealth) effective July 5, 2013.  The Company also filed a lawsuit in Franklin Circuit Court against the Commonwealth seeking a declaration of the Company's right to terminate the contract on July 5, 2013.  In April 2013, the Commonwealth answered that lawsuit and filed counterclaims against the Company seeking declaratory relief and damages.  In May 2013, the Franklin Circuit Court ruled that Kentucky Spirit does not have a contractual right to terminate the contract early.  Kentucky Spirit has appealed that ruling to the Kentucky Court of Appeals.
	The Company also filed a formal dispute with the Cabinet for damages incurred under the contract, which was later appealed to and denied by the Finance and Administration Cabinet.  In response, the Company filed a lawsuit in April 2013, in Franklin Circuit Court seeking damages against the Commonwealth for losses sustained due to the Commonwealth's alleged breaches. This lawsuit was subsequently consolidated with the original lawsuit for declaratory relief and continues to proceed.
	Kentucky Spirit's efforts to resolve issues with the Commonwealth were unsuccessful and on July 5, 2013, Kentucky Spirit proceeded with its previously announced exit.  The Commonwealth has alleged that Kentucky Spirit's exit constitutes a material breach of contract.  The Commonwealth seeks to recover substantial damages and to enforce its rights under Kentucky Spirit's $25,000 performance bond.  Any claim for damages by the Commonwealth may include the costs of transition and the additional costs to the Commonwealth to cover Kentucky Spirit's former members through July 5, 2014. Kentucky Spirit is pursuing its litigation claims for damages against the Commonwealth and will vigorously defend against any allegations that it has breached the contract.
	The resolution of the Kentucky litigation matters may result in a range of possible outcomes.  If the Company prevails on its claims, Kentucky Spirit would be entitled to damages under its lawsuit.  If the Commonwealth prevails, a liability to the Commonwealth could be recorded.  The Company is unable to estimate the ultimate outcome resulting from the Kentucky litigation.  As a result, the Company has not recorded any receivable or any liability for potential damages under the contract as of September 30, 2013.  While uncertain, the ultimate resolution of the pending litigation could have a material effect on the results of operations of the Company in the period it is resolved or becomes known.
	Excluding the Kentucky matters discussed above, the Company is also routinely subjected to legal proceedings in the normal course of business.  While the ultimate resolution of such matters in the normal course of business is uncertain, the Company does not expect the results of any of these matters individually, or in the aggregate, to have a material effect on its financial position or results of operations.

ShortTerm_And_LongTerm_Investm1

Short-Term And Long-Term Investments And Restricted Deposits (Tables)	9 Months Ended
	Sep. 30, 2013
Investments, Debt and Equity Securities [Abstract]
Short-Term And Long-Term Investments And Restricted Deposits By Investment Type	Short-term and Long-term Investments and Restricted Deposits
	Short-term and long-term investments and restricted deposits by investment type consist of the following:
		September 30, 2013										December 31, 2012
		Amortized			Gross		Gross			Fair		Amortized			Gross		Gross			Fair
		Cost			Unrealized		Unrealized Losses			Value		Cost			Unrealized		Unrealized Losses			Value
					Gains										Gains
	U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	247,051		$	308	$	(6,196	)	$	241,163	$	117,434		$	594	$	(221	)	$	117,807
	Corporate securities	327,083			3,115		(650		)	329,548		315,807			5,101		(198		)	320,710
	Restricted certificates of deposit	5,891			—		—			5,891		5,890			—		—			5,890
	Restricted cash equivalents	22,608			—		—			22,608		14,460			—		—			14,460
	Municipal securities:
	General obligation	61,101			544		(169		)	61,476		88,690			1,173		(26		)	89,837
	Pre-refunded	14,329			164		(1		)	14,492		5,337			85		—			5,422
	Revenue	76,753			534		(538		)	76,749		84,726			1,331		(30		)	86,027
	Variable rate demand notes	65,955			—		—			65,955		37,685			—		—			37,685
	Asset backed securities	128,343			656		(256		)	128,743		83,295			1,197		(17		)	84,475
	Cost and equity method investments	18,538			—		—			18,538		11,298			—		—			11,298
	Life insurance contracts	15,289			—		—			15,289		15,023			—		—			15,023
	Total	$	982,941		$	5,321	$	(7,810	)	$	980,452	$	779,645		$	9,481	$	(492	)	$	788,634
Fair Value Of Available-For-Sale Investments With Gross Unrealized Losses By Investment Type And Length Of Time	The fair value of available-for-sale investments with gross unrealized losses by investment type and length of time that individual securities have been in a continuous unrealized loss position were as follows:
		September 30, 2013										December 31, 2012
		Less Than 12 Months					12 Months or More					Less Than 12 Months					12 Months or More
		Unrealized Losses			Fair		Unrealized Losses			Fair		Unrealized Losses			Fair		Unrealized Losses			Fair
					Value					Value					Value					Value
	U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	(6,196	)	$	196,888	$	—		$	—	$	(219	)	$	56,033	$	(2	)	$	202
	Corporate securities	(641		)	79,753		(9		)	42		(198		)	44,758		—			—
	Municipal securities:
	General obligation	(119		)	9,264		(50		)	2,453		(26		)	8,464		—			—
	Pre-refunded	(1		)	489		—			—		—			—		—			—
	Revenue	(531		)	28,866		(7		)	1,807		(30		)	3,325		—			—
	Asset backed securities	(256		)	35,140		—			—		(17		)	9,321		—			—
	Total	$	(7,744	)	$	350,400	$	(66	)	$	4,302	$	(490	)	$	121,901	$	(2	)	$	202
Contractual Maturities Of Short-Term And Long-Term Investments And Restricted Deposits	The contractual maturities of short-term and long-term investments and restricted deposits are as follows:
		September 30, 2013										December 31, 2012
		Investments					Restricted Deposits					Investments					Restricted Deposits
		Amortized			Fair		Amortized			Fair		Amortized			Fair		Amortized			Fair
		Cost			Value		Cost			Value		Cost			Value		Cost			Value
	One year or less	$	121,753		$	122,631	$	36,600		$	36,606	$	138,011		$	139,118	$	34,403		$	34,435
	One year through five years	588,145			589,585		4,302			4,305		474,068			481,381		358			358
	Five years through ten years	169,250			164,201		—			—		94,006			93,878		—			—
	Greater than ten years	62,891			63,124		—			—		38,799			39,464		—			—
	Total	$	942,039		$	939,541	$	40,902		$	40,911	$	744,884		$	753,841	$	34,761		$	34,793

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]
Fair Value Measurements By Level For Assets And Liabilities Measured At Fair Value On A Recurring Basis	The following table summarizes fair value measurements by level at September 30, 2013, for assets and liabilities measured at fair value on a recurring basis:
		Level I		Level II		Level III		Total
	Assets
	Cash and cash equivalents	$	741,281	$	—	$	—	$	741,281
	Investments available for sale:
	U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	213,772	$	14,979	$	—	$	228,751
	Corporate securities	—		329,548		—		329,548
	Municipal securities:
	General obligation	—		61,476		—		61,476
	Pre-refunded	—		14,492		—		14,492
	Revenue	—		76,749		—		76,749
	Variable rate demand notes	—		65,955		—		65,955
	Asset backed securities	—		128,743		—		128,743
	Total investments	$	213,772	$	691,942	$	—	$	905,714
	Restricted deposits available for sale:
	Cash and cash equivalents	$	22,608	$	—	$	—	$	22,608
	Certificates of deposit	5,891		—		—		5,891
	U.S. Treasury securities and obligations of U.S. government corporations and agencies	12,412		—		—		12,412
	Total restricted deposits	$	40,911	$	—	$	—	$	40,911
	Other long-term assets: Interest rate swap contract	$	—	$	10,596	$	—	$	10,596
	Total assets at fair value	$	995,964	$	702,538	$	—	$	1,698,502
	The following table summarizes fair value measurements by level at December 31, 2012, for assets and liabilities measured at fair value on a recurring basis:
		Level I		Level II		Level III		Total
	Assets
	Cash and cash equivalents	$	843,952	$	—	$	—	$	843,952
	Investments available for sale:
	U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	57,114	$	46,250	$	—	$	103,364
	Corporate securities	—		320,710		—		320,710
	Municipal securities:
	General obligation	—		89,837		—		89,837
	Pre-refunded	—		5,422		—		5,422
	Revenue	—		86,027		—		86,027
	Variable rate demand notes	—		37,685		—		37,685
	Asset backed securities	—		84,475		—		84,475
	Total investments	$	57,114	$	670,406	$	—	$	727,520
	Restricted deposits available for sale:
	Cash and cash equivalents	$	14,460	$	—	$	—	$	14,460
	Certificates of deposit	5,890		—		—		5,890
	U.S. Treasury securities and obligations of U.S. government corporations and agencies	14,443		—		—		14,443
	Total restricted deposits	$	34,793	$	—	$	—	$	34,793
	Other long-term assets: Interest rate swap contract	$	—	$	16,304	$	—	$	16,304
	Total assets at fair value	$	935,859	$	686,710	$	—	$	1,622,569

Debt_Tables

Debt (Tables)	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]
Schedule Of Debt	Debt consists of the following:
		September 30, 2013			December 31, 2012
	Senior notes, at par	$	425,000		$	425,000
	Unamortized premium on senior notes	6,495			7,823
	Interest rate swap fair value	10,596			16,304
	Senior notes	442,091			449,127
	Revolving credit agreement	—			—
	Mortgage notes payable	73,447			84,081
	Capital leases and other	5,439			5,646
	Total debt	520,977			538,854
	Less current portion	(3,046		)	(3,373		)
	Long-term debt	$	517,931		$	535,481

Earnings_Loss_Per_Share_Tables

Earnings (Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]
Calculation Of Basic And Diluted Net Earnings Per Common Share	The following table sets forth the calculation of basic and diluted net earnings per common share:
		Three Months Ended September 30,				Nine Months Ended September 30,
		2013		2012		2013		2012
	Net earnings (loss) attributable to Centene Corporation	$	49,373	$	3,819	$	111,859	$	(7,202	)
	Shares used in computing per share amounts:
	Weighted average number of common shares outstanding	54,679,660		51,584,860		53,863,779		51,393,345
	Common stock equivalents (as determined by applying the treasury stock method)	2,253,396		2,221,337		2,092,642		—
	Weighted average number of common shares and potential dilutive common shares outstanding	56,933,056		53,806,197		55,956,421		51,393,345
	Net earnings (loss) per share attributable to Centene Corporation:
	Basic earnings (loss) per common share	$	0.9	$	0.07	$	2.08	$	(0.14	)
	Diluted earnings (loss) per common share	$	0.87	$	0.07	$	2	$	(0.14	)

Segment_Information_Tables

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]
Segment Information	Segment information for the three months ended September 30, 2013, follows:
		Medicaid			Specialty		Eliminations			Consolidated
		Managed Care			Services					Total
	Premium and service revenues from external customers	$	2,510,221		$	223,927	$	—		$	2,734,148
	Premium and service revenues from internal customers	9,885			542,238		(552,123		)	—
	Total premium and service revenues	$	2,520,106		$	766,165	$	(552,123	)	$	2,734,148
	Earnings from operations	$	68,083		$	14,148	$	—		$	82,231
	Segment information for the three months ended September 30, 2012, follows:
		Medicaid			Specialty		Eliminations			Consolidated
		Managed Care			Services					Total
	Premium and service revenues from external customers	$	2,072,079		$	140,385	$	—		$	2,212,464
	Premium and service revenues from internal customers	25,138			442,388		(467,526		)	—
	Total premium and service revenues	$	2,097,217		$	582,773	$	(467,526	)	$	2,212,464
	Earnings (loss) from operations	$	(55,239	)	$	27,598	$	—		$	(27,641	)
	Segment information for the nine months ended September 30, 2013, follows:
		Medicaid			Specialty		Eliminations			Consolidated
		Managed Care			Services					Total
	Premium and service revenues from external customers	$	7,367,236		$	543,472	$	—		$	7,910,708
	Premium and service revenues from internal customers	31,050			1,660,639		(1,691,689		)	—
	Total premium and service revenues	$	7,398,286		$	2,204,111	$	(1,691,689	)	$	7,910,708
	Earnings from operations	$	116,609		$	72,752	$	—		$	189,361
	Segment information for the nine months ended September 30, 2012, follows:
		Medicaid			Specialty		Eliminations			Consolidated
		Managed Care			Services					Total
	Premium and service revenues from external customers	$	5,507,972		$	429,559	$	—		$	5,937,531
	Premium and service revenues from internal customers	62,751			1,206,293		(1,269,044		)	—
	Total premium and service revenues	$	5,570,723		$	1,635,852	$	(1,269,044	)	$	5,937,531
	Earnings (loss) from operations	$	(72,740	)	$	32,551	$	—		$	(40,189	)

Acquisition_Details

Acquisition (Details) (USD $)	9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Apr. 30, 2013
Acquisition [Abstract]
Business Acquisition, Percentage of Voting Interests Acquired			100.00%
Business Acquisition, Cost of Acquired Entity, Purchase Price			$142,495
Common stock issued for acquisition	75,425	0
Business Acquisition, Cost of Acquired Entity, Cash Paid			67,070
Common stock issued for stock offering (in shares)	342,640
Common stock issued for stock offering	15,225
Business Acquisition, Purchase Price Allocation, Goodwill Amount			91,260
Business Acquisition, Purchase Price Allocation, Intangible Assets			$35,000

ShortTerm_And_LongTerm_Investm2

Short-Term And Long-Term Investments And Restricted Deposits (Narrative) (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
	positions
Investments, Debt and Equity Securities [Abstract]
Percentage of investments in securities recorded at fair value that carry a rating by Moody's or S&P of AAA/Aaa	47.00%
Percentage of investments in securities recorded at fair value that carry a rating by Moody's or S&P of AA-/Aa3 or higher	66.00%
Percentage of investments in securities recorded at fair value that carry a rating by Moody's or S&P of A-/A3 or higher	94.00%
Positions from which gross unrealized losses were generated	89
Total positions	356
Investment amortization	$7,612	$8,676

ShortTerm_And_LongTerm_Investm3

Short-Term And Long-Term Investments And Restricted Deposits (Short-Term And Long-Term Investments And Restricted Deposits By Investment Type) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	$982,941	$779,645
Gross Unrealized Gains	5,321	9,481
Gross Unrealized Losses	-7,810	-492
Fair Value	980,452	788,634
U.S. Treasury Securities And Obligations Of U.S. Government Corporations And Agencies [Member]
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	247,051	117,434
Gross Unrealized Gains	308	594
Gross Unrealized Losses	-6,196	-221
Fair Value	241,163	117,807
Corporate Securities [Member]
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	327,083	315,807
Gross Unrealized Gains	3,115	5,101
Gross Unrealized Losses	-650	-198
Fair Value	329,548	320,710
Restricted Certificates Of Deposit [Member]
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	5,891	5,890
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	5,891	5,890
Restricted Cash Equivalents [Member]
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	22,608	14,460
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	22,608	14,460
Municipal Securities, General Obligation [Member]
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	61,101	88,690
Gross Unrealized Gains	544	1,173
Gross Unrealized Losses	-169	-26
Fair Value	61,476	89,837
Municipal Securities, Pre-Refunded [Member]
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	14,329	5,337
Gross Unrealized Gains	164	85
Gross Unrealized Losses	-1	0
Fair Value	14,492	5,422
Municipal Securities, Revenue [Member]
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	76,753	84,726
Gross Unrealized Gains	534	1,331
Gross Unrealized Losses	-538	-30
Fair Value	76,749	86,027
Municipal Securities, Variable Rate Demand Notes [Member]
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	65,955	37,685
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	65,955	37,685
Asset Backed Securities [Member]
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	128,343	83,295
Gross Unrealized Gains	656	1,197
Gross Unrealized Losses	-256	-17
Fair Value	128,743	84,475
Cost And Equity Method Investments [Member]
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	18,538	11,298
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	18,538	11,298
Life Insurance Contracts [Member]
Schedule Of Investments And Restricted Deposits By Type [Line Items]
Amortized Cost	15,289	15,023
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	$15,289	$15,023

ShortTerm_And_LongTerm_Investm4

Short-Term And Long-Term Investments And Restricted Deposits (Fair Value Of Available-For-Sale Investments With Gross Unrealized Losses By Investment Type And Length Of Time) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Unrealized Losses	($7,744)	($490)
Less Than 12 Months, Fair Value	350,400	121,901
12 Months or More, Unrealized Losses	-66	-2
12 Months or More, Fair Value	4,302	202
U.S. Treasury Securities And Obligations Of U.S. Government Corporations And Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Unrealized Losses	-6,196	-219
Less Than 12 Months, Fair Value	196,888	56,033
12 Months or More, Unrealized Losses	0	-2
12 Months or More, Fair Value	0	202
Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Unrealized Losses	-641	-198
Less Than 12 Months, Fair Value	79,753	44,758
12 Months or More, Unrealized Losses	-9	0
12 Months or More, Fair Value	42	0
Municipal Securities, General Obligation [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Unrealized Losses	-119	-26
Less Than 12 Months, Fair Value	9,264	8,464
12 Months or More, Unrealized Losses	-50	0
12 Months or More, Fair Value	2,453	0
Municipal Securities, Pre-Refunded [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Unrealized Losses	-1	0
Less Than 12 Months, Fair Value	489	0
12 Months or More, Unrealized Losses	0	0
12 Months or More, Fair Value	0	0
Municipal Securities, Revenue [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Unrealized Losses	-531	-30
Less Than 12 Months, Fair Value	28,866	3,325
12 Months or More, Unrealized Losses	-7	0
12 Months or More, Fair Value	1,807	0
Asset Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Unrealized Losses	-256	-17
Less Than 12 Months, Fair Value	35,140	9,321
12 Months or More, Unrealized Losses	0	0
12 Months or More, Fair Value	$0	$0

ShortTerm_And_LongTerm_Investm5

Short-Term And Long-Term Investments And Restricted Deposits (Contractual Maturities Of Short-Term And Long-Term Investments And Restricted Deposits) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
One year or less, Amortized Cost	$121,753	$138,011
One year through five years, Amortized Cost	588,145	474,068
Five years through ten years, Amortized Cost	169,250	94,006
Greater than ten years, Amortized Cost	62,891	38,799
Total, Amortized Cost	942,039	744,884
One year or less, Fair Value	122,631	139,118
One year through five years, Fair Value	589,585	481,381
Five years through ten years, Fair Value	164,201	93,878
Greater than ten years, Fair Value	63,124	39,464
Total, Fair Value	939,541	753,841
Restricted Deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
One year or less, Amortized Cost	36,600	34,403
One year through five years, Amortized Cost	4,302	358
Five years through ten years, Amortized Cost	0	0
Greater than ten years, Amortized Cost	0	0
Total, Amortized Cost	40,902	34,761
One year or less, Fair Value	36,606	34,435
One year through five years, Fair Value	4,305	358
Five years through ten years, Fair Value	0	0
Greater than ten years, Fair Value	0	0
Total, Fair Value	$40,911	$34,793

Fair_Value_Measurements_Narrat

Fair Value Measurements (Narrative) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value Disclosures [Abstract]
Transfers from Level I to Level II	$101
Transfers from Level II to Level I	26,571
Life insurance contracts and other non-majority owned investments, fair value	$33,827	$26,321

Fair_Value_Measurements_Fair_V

Fair Value Measurements (Fair Value Measurements By Level For Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Cash and Cash Equivalents	$741,281	$843,952
U.S. Treasury securities and obligations of U.S. government corporations and agencies	228,751	103,364
Corporate securities	329,548	320,710
Municipal securities, General obligation	61,476	89,837
Municipal securities, Pre-refunded	14,492	5,422
Municipal securities, Revenue	76,749	86,027
Municipal securities, Variable rate demand notes	65,955	37,685
Asset backed securities	128,743	84,475
Total investments	905,714	727,520
Cash and cash equivalents	22,608	14,460
Certificates of deposit	5,891	5,890
U.S. Treasury securities and obligations of U.S. government corporations and agencies	12,412	14,443
Total restricted deposits	40,911	34,793
Interest rate swap contract	10,596	16,304
Total assets at fair value	1,698,502	1,622,569
Level I [Member]
Cash and Cash Equivalents	741,281	843,952
U.S. Treasury securities and obligations of U.S. government corporations and agencies	213,772	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
Total investments	213,772	57,114
Cash and cash equivalents	22,608	14,460
Certificates of deposit	5,891	5,890
U.S. Treasury securities and obligations of U.S. government corporations and agencies	12,412	14,443
Total restricted deposits	40,911	34,793
Interest rate swap contract	0	0
Total assets at fair value	995,964	935,859
Level II [Member]
Cash and Cash Equivalents	0	0
U.S. Treasury securities and obligations of U.S. government corporations and agencies	14,979	46,250
Corporate securities	329,548	320,710
Municipal securities, General obligation	61,476	89,837
Municipal securities, Pre-refunded	14,492	5,422
Municipal securities, Revenue	76,749	86,027
Municipal securities, Variable rate demand notes	65,955	37,685
Asset backed securities	128,743	84,475
Total investments	691,942	670,406
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	10,596	16,304
Total assets at fair value	702,538	686,710
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
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

Debt_Narrative_Details

Debt (Narrative) (Details) (USD $)	2 Months Ended	9 Months Ended		1 Months Ended
	Jun. 30, 2013	Sep. 30, 2013	Dec. 31, 2012	Nov. 30, 2012	31-May-11
				5.75% Senior Notes [Member]	5.75% Senior Notes [Member]
Debt Instrument [Line Items]
Senior notes, at par		$425,000,000	$425,000,000	$175,000,000	$250,000,000
Interest rate on notes, percentage				5.75%	5.75%
Senior notes due date				1-Jun-17	1-Jun-17
Senior notes, effective yield				4.29%	6.00%
Debt Instrument, Unamortized Premium		6,495,000	7,823,000
Interest rate swap fair value		10,596,000	16,304,000
Variable rate of swap, percentage		3.76%
Revolving credit facility, maximum borrowing capacity		500,000,000
Line of Credit Facility, Amount Outstanding		0
Line of Credit Facility, Covenant Terms	The agreement contains non-financial and financial covenants, including requirements of minimum fixed charge coverage ratios, maximum debt-to-EBITDA ratios and minimum tangible net worth. The Company is required not to exceed a maximum debt-to-EBITDA ratio of 3.25 as of September 30, 2013 and 3.0 as of December 31, 2013 and thereafter.
Line of Credit Facility, Current Borrowing Capacity		400,000,000
Mortgage Loans on Real Estate			0
Revolving credit facility, due date		1-Jun-18
Compensating Balance, Amount		0
Revolving credit agreement		0	0
Letters of credit outstanding amount		$28,682,000
Letters of credit bore interest		0.52%

Debt_Schedule_Of_Debt_Details

Debt (Schedule Of Debt) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Debt Disclosure [Abstract]
Senior notes, at par	$425,000	$425,000
Debt Instrument, Unamortized Premium	6,495	7,823
Interest rate swap fair value	10,596	16,304
Senior notes	442,091	449,127
Revolving credit agreement	0	0
Mortgage notes payable	73,447	84,081
Capital leases and other	5,439	5,646
Total debt	520,977	538,854
Less current portion	-3,046	-3,373
Long-term debt	$517,931	$535,481

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)	9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013
Stockholders' Equity Attributable to Parent [Abstract]
Common stock issued for acquisition (in shares)	1,716,690
Common stock issued for stock offering (in shares)	342,640
Common stock issued for stock offering	$15,225

Earnings_Loss_Per_Share_Detail

Earnings (Loss) Per Share (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]
Net earnings (loss) attributable to Centene Corporation	$49,373	$3,819	$111,859	($7,202)
Weighted average number of common shares outstanding (in shares)	54,679,660	51,584,860	53,863,779	51,393,345
Common stock equivalents (as determined by applying the treasury stock method)	2,253,396	2,221,337	2,092,642	0
Weighted average number of common shares and potential dilutive common shares outstanding (in shares)	56,933,056	53,806,197	55,956,421	51,393,345
Basic earnings (loss) per common share (in dollars per share)	$0.90	$0.07	$2.08	($0.14)
Diluted earnings (loss) per common share (in dollars per share)	$0.87	$0.07	$2	($0.14)
Anti-dilutive stock options, restricted stock and restricted stock units excluded from the calculation of diluted earnings per common share	14,532	44,642	76,957	4,638,757

Segment_Information_Details

Segment Information (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
			segments	segments
Number of reportable segments			2	2
Premium and service revenues from external customers	$2,734,148	$2,212,464	$7,910,708	$5,937,531
Premium and service revenues from internal customers	0	0	0	0
Premium and service revenues	2,734,148	2,212,464	7,910,708	5,937,531
Earnings (loss) from operations	82,231	-27,641	189,361	-40,189
Medicaid Managed Care [Member]
Premium and service revenues from external customers	2,510,221	2,072,079	7,367,236	5,507,972
Premium and service revenues from internal customers	9,885	25,138	31,050	62,751
Premium and service revenues	2,520,106	2,097,217	7,398,286	5,570,723
Earnings (loss) from operations	68,083	-55,239	116,609	-72,740
Specialty Services [Member]
Premium and service revenues from external customers	223,927	140,385	543,472	429,559
Premium and service revenues from internal customers	542,238	442,388	1,660,639	1,206,293
Premium and service revenues	766,165	582,773	2,204,111	1,635,852
Earnings (loss) from operations	14,148	27,598	72,752	32,551
Eliminations [Member]
Premium and service revenues from external customers	0	0	0	0
Premium and service revenues from internal customers	-552,123	-467,526	-1,691,689	-1,269,044
Premium and service revenues	-552,123	-467,526	-1,691,689	-1,269,044
Earnings (loss) from operations	$0	$0	$0	$0

Contingencies_Details

Contingencies (Details)	9 Months Ended
	Sep. 30, 2013
Contingency [Abstract]
Loss Contingency, Allegations	In October 2012, the Company notified the Kentucky Cabinet for Health and Family Services (Cabinet) that it was exercising a contractual right that it believes allows the Company to terminate its Medicaid managed care contract with the Commonwealth of Kentucky (Commonwealth) effective July 5, 2013.B The Company also filed a lawsuit in Franklin Circuit Court against the Commonwealth seeking a declaration of the Company's right to terminate the contract on July 5, 2013.B In April 2013, the Commonwealth answered that lawsuit and filed counterclaims against the Company seeking declaratory relief and damages.B In May 2013, the Franklin Circuit Court ruled that Kentucky Spirit does not have a contractual right to terminate the contract early.B Kentucky Spirit has appealed that ruling to the Kentucky Court of Appeals. The Company also filed a formal dispute with the Cabinet for damages incurred under the contract, which was later appealed to and denied by the Finance and Administration Cabinet.B In response, the Company filed a lawsuit in April 2013, in Franklin Circuit Court seeking damages against the Commonwealth for losses sustained due to the Commonwealth's alleged breaches. This lawsuit was subsequently consolidated with the original lawsuit for declaratory relief and continues to proceed. Kentucky Spirit's efforts to resolve issues with the Commonwealth were unsuccessful and on July 5, 2013, Kentucky Spirit proceeded with its previously announced exit.B By letter dated July 11, 2013, the Commonwealth alleged that Kentucky Spirit's exit constitutes a material breach of contract.B The letter states that, unless Kentucky Spirit cures the alleged material breach within thirty days, the Commonwealth will seek to recover substantial damages and to enforce its rights under Kentucky Spirit's $25,000 performance bond.B Any claim for damages by the Commonwealth may include the costs of transition and the additional costs to the Commonwealth to cover Kentucky Spirit's former members through July 5, 2014. Kentucky Spirit is pursuing its litigation claims for damages against the Commonwealth and will vigorously defend against any allegations that it has breached the contract.
Loss Contingency, Inestimable Loss	The resolution of the Kentucky litigation matters may result in a range of possible outcomes.B If the Company prevails on its claims, Kentucky Spirit would be entitled to damages under its lawsuit.B If the Commonwealth prevails, a liability to the Commonwealth could be recorded.B The Company is unable to estimate the ultimate outcome resulting from the Kentucky litigation.B As a result, the Company has not recorded any receivable or any liability for potential damages under the contract as of September 30, 2013.B While uncertain, the ultimate resolution of the pending litigation could have a material effect on the results of operations of the Company in the period it is resolved or becomes known.