COMMITMENTS AND CONTINGENCIES (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Minimum lease payments [Abstract]
2013	$ 31,963,000
2014	24,832,000
2015	20,067,000
2016	17,976,000
2017	15,324,000
Thereafter	42,028,000
Total	152,190,000
Minimum sublease income [Abstract]
2013	(777,000)
2014	(426,000)
2015	(439,000)
2016	(452,000)
2017	(76,000)
Thereafter	0
Total	(2,170,000)
Minimum lease payments, net of sublease income [Abstract]
2013	31,186,000
2014	24,406,000
2015	19,628,000
2016	17,524,000
2017	15,248,000
Thereafter	42,028,000
Total	150,020,000
Original lease terms, at maximum (in years)	13 years
Rent expense	33,900,000	33,300,000	32,400,000
Capitation Arrangements [Abstract]
Medical costs associated with capitation arrangements (in hundredths)	9.00%	8.20%	6.40%
Putative Securities Class Action Lawsuit [Member]
Loss Contingencies [Line Items]
Number of current and former officers named in legal matter	3
Number of additional shareholders filing similar motions	3
Total number of shareholders in legal matter	4
Company self insured rentention	2,500,000
Putative ERISA Class Action Lawsuit [Member]
Loss Contingencies [Line Items]
Number of former employees that filed lawsuit	2
Number of additional actions filed in legal matter	3
Putative Securities Class Action Lawsuit Related to Aetna Deal - Court of Chancery of the State of Delaware [Member]
Loss Contingencies [Line Items]
Total number of shareholders in legal matter	4
Original termination fee	167,500,000
New Termination Fee	100,000,000
Medicare eligibility for Workers’ Compensation Medicare product [Member]
Loss Contingencies [Line Items]
Civil monetary settlement agreement	$ 3,000,000
Putative Securities Class Action Lawsuit Related to Aetna Deal - Circuit Court for Montgomery County, Maryland [Member]
Loss Contingencies [Line Items]
Total number of shareholders in legal matter	3