Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011 Y contract	Dec. 31, 2010	Dec. 31, 2009
Net revenues
Managed Care Revenue									$ 2,200,000,000	$ 2,400,000,000	$ 2,200,000,000
Fee-For-Service and Cost-Plus Contracts Revenue									174,500,000	192,900,000	104,400,000
Block Grant Revenues									114,400,000	109,100,000	106,600,000
Dispensing Revenue									247,400,000	234,800,000	221,600,000
Performance-Based Revenue									26,500,000	13,100,000	7,600,000
Rebate revenues									32,800,000	25,500,000	29,400,000
Significant customers
Revenues generated	721,464,000	686,843,000	698,338,000	692,755,000	749,210,000	750,319,000	741,658,000	728,053,000	2,799,400,000	2,969,240,000	2,641,814,000
Number of contract extensions available under option									3
Contract extension period available under option (in years)									1
Minimum number of contracts per customer									1
Maricopa County Regional Behavioral Health Authority
Significant customers
Revenues generated									779,500,000	807,100,000	725,000,000
Number of members receiving behavioral healthcare management and other related services									715,000
Termination notice (in days)									10
Maricopa County Regional Behavioral Health Authority | Service
Significant customers
Major customer defined (as a percent)									10.00%	10.00%	10.00%
Wellpoint, Inc.
Significant customers
Revenues generated										175,700,000	170,400,000
Commercial
Significant customers
Revenues generated									561,780,000	652,221,000	650,139,000
Commercial | Customer A | Service
Significant customers
Revenues generated									171,109,000	243,399,000	235,002,000
Commercial | Customer B | Service
Significant customers
Revenues generated									67,049,000	71,338,000	85,842,000
Commercial | Customer C | Service
Significant customers
Revenues generated									111,607,000	65,175,000	40,697,000
Public Sector
Significant customers
Revenues generated									1,459,659,000	1,442,093,000	1,362,420,000
Public Sector | Customer D | Service
Significant customers
Revenues generated									191,063,000	153,650,000	147,734,000
Radiology Benefits Management
Significant customers
Revenues generated									344,335,000	454,105,000	305,251,000
Radiology Benefits Management | Wellpoint, Inc. | Service
Significant customers
Revenues generated										159,644,000	155,933,000
Radiology Benefits Management | Customer E | Service
Significant customers
Revenues generated									134,257,000	121,401,000
Radiology Benefits Management | Customer F | Service
Significant customers
Revenues generated									38,297,000	66,970,000	80,368,000
Radiology Benefits Management | Customer G | Service
Significant customers
Revenues generated									55,197,000	51,877,000	23,331,000
Radiology Benefits Management | Customer H | Service
Significant customers
Revenues generated									36,293,000	10,448,000
Specialty Pharmaceutical Management
Significant customers
Revenues generated									295,943,000	270,646,000	259,745,000
Specialty Pharmaceutical Management | Customer E | Service
Significant customers
Revenues generated									25,006,000	32,877,000	30,856,000
Specialty Pharmaceutical Management | Customer I | Service
Significant customers
Revenues generated									90,563,000	86,850,000	85,725,000
Specialty Pharmaceutical Management | Customer J | Service
Significant customers
Revenues generated									56,115,000	57,198,000	43,937,000
Specialty Pharmaceutical Management | Customer Q | Service
Significant customers
Revenues generated									18,943,000	24,897,000	42,465,000
Medicaid Administration
Significant customers
Revenues generated									220,453,000	176,283,000	64,259,000
Medicaid Administration | Customer P | Service
Significant customers
Revenues generated									22,084,000	16,249,000	6,036,000
Medicaid Administration | Customer K | Service
Significant customers
Revenues generated									28,060,000	31,145,000	11,353,000
Medicaid Administration | Customer L | Service
Significant customers
Revenues generated									82,770,000	26,108,000
Medicaid Administration | Customer M | Service
Significant customers
Revenues generated									23,683,000	24,432,000	10,528,000
Medicaid Administration | Customer N | Service
Significant customers
Revenues generated									18,924,000	22,000,000	8,995,000
Medicaid Administration | Customer O | Service
Significant customers
Revenues generated										$ 10,319,000	$ 8,815,000