Sale of Medicare PDP Business and Northeast Business (Details) (USD $)	3 Months Ended					12 Months Ended			0 Months Ended		3 Months Ended	12 Months Ended				12 Months Ended
	Dec. 31, 2012 Customers	Sep. 30, 2012	Jun. 30, 2012	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012 Customers	Dec. 31, 2011	Dec. 31, 2010	Apr. 02, 2012 Divested Operations and Services [Member]	Apr. 02, 2012 Medicare PDP Business [Member] Customers	Jun. 30, 2012 Medicare PDP Business [Member]	Dec. 31, 2012 Medicare PDP Business [Member] Customers	Dec. 31, 2011 Medicare PDP Business [Member] Customers	Dec. 31, 2010 Medicare PDP Business [Member]	Apr. 02, 2012 Medicare PDP Business [Member] Divested Operations and Services [Member]	Dec. 31, 2012 Northeast Operations [Member]	Dec. 31, 2011 Northeast Operations [Member]	Dec. 31, 2010 Northeast Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal date										Apr. 01, 2012
Proceeds from divestiture of business						$ 0	$ 162,101,000	$ 76,126,000		$ 169,900,000	$ 78,300,000
Adjustment to loss on sale of Northeast health plan subsidiaries				(6,300,000)	(34,900,000)	0	(40,815,000)	(41,959,000)								0	40,800,000	42,000,000
Sales price component										400
Number of customers	5,400,000					5,400,000				424,820		0	382,000
Pretax gain on sale of business												132,800,000
Gain on sale of discontinued operation, net of tax	(2,200,000)	(2,400,000)	119,400,000			114,834,000	0	0				114,800,000
Deferred revenue	0					0	0								12,000,000
Deferred revenue, recognition period															9 months
Discount rate									1.20%
Disposal group, revenues related to divested business												192,100,000	485,600,000	504,400,000
Disposal group, pretax income (loss) related to divested business												$ (28,800,000)	$ 17,200,000	$ 50,300,000