Fair Value Measurements (Quantitative Information About Level 3 Fair Value Measurements) (Details) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Goodwill	$ 565,886,000	$ 565,886,000
Western Region Operations [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Goodwill	565,900,000	565,900,000
Level 3 [Member] | Monte Carlo Simulation Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Embedded contractual derivative asset	10,800,000	11,200,000
Embedded contractual derivative liability	4,800,000	3,200,000
Level 3 [Member] | Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Lease impairment obligation		7,400,000
Level 3 [Member] | Western Region Operations [Member] | Income Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Goodwill	$ 565,900,000	$ 565,900,000
Level 3 [Member] | Embedded contractual derivative asset [Member] | Monte Carlo Simulation Approach [Member] | Health Net Health Care Expenditures [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Health Care Expenditures, range (as a percentage)	(0.20%)	(1.70%)
Level 3 [Member] | Embedded contractual derivative asset [Member] | Monte Carlo Simulation Approach [Member] | Health Net Health Care Expenditures [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Health Care Expenditures, range (as a percentage)	(0.20%)	0.80%
Level 3 [Member] | Embedded contractual derivative asset [Member] | Monte Carlo Simulation Approach [Member] | Health Net Health Care Expenditures [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Health Care Expenditures, range (as a percentage)	(0.20%)	(0.40%)
Level 3 [Member] | Embedded contractual derivative asset [Member] | Monte Carlo Simulation Approach [Member] | National Health Care Expenditures [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Health Care Expenditures, range (as a percentage)	3.70%	3.70%
Level 3 [Member] | Embedded contractual derivative asset [Member] | Monte Carlo Simulation Approach [Member] | National Health Care Expenditures [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Health Care Expenditures, range (as a percentage)	3.70%	3.70%
Level 3 [Member] | Embedded contractual derivative asset [Member] | Monte Carlo Simulation Approach [Member] | National Health Care Expenditures [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Health Care Expenditures, range (as a percentage)	3.70%	3.70%
Level 3 [Member] | Embedded contractual derivative liability [Member] | Monte Carlo Simulation Approach [Member] | Health Net Health Care Expenditures [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Health Care Expenditures, range (as a percentage)	(6.60%)	(0.30%)
Level 3 [Member] | Embedded contractual derivative liability [Member] | Monte Carlo Simulation Approach [Member] | Health Net Health Care Expenditures [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Health Care Expenditures, range (as a percentage)	11.00%	10.10%
Level 3 [Member] | Embedded contractual derivative liability [Member] | Monte Carlo Simulation Approach [Member] | Health Net Health Care Expenditures [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Health Care Expenditures, range (as a percentage)	3.70%	4.90%
Level 3 [Member] | Embedded contractual derivative liability [Member] | Monte Carlo Simulation Approach [Member] | National Health Care Expenditures [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Health Care Expenditures, range (as a percentage)	(3.98%)	(0.10%)
Level 3 [Member] | Embedded contractual derivative liability [Member] | Monte Carlo Simulation Approach [Member] | National Health Care Expenditures [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Health Care Expenditures, range (as a percentage)	8.38%	7.30%
Level 3 [Member] | Embedded contractual derivative liability [Member] | Monte Carlo Simulation Approach [Member] | National Health Care Expenditures [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Health Care Expenditures, range (as a percentage)	2.70%	3.30%
Level 3 [Member] | Goodwill [Member] | Western Region Operations [Member] | Income Approach [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount Rate, range (as a percentage)	10.00%	9.00%
Level 3 [Member] | Goodwill [Member] | Western Region Operations [Member] | Income Approach [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount Rate, range (as a percentage)	10.00%	9.00%
Level 3 [Member] | Goodwill [Member] | Western Region Operations [Member] | Income Approach [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount Rate, range (as a percentage)	10.00%	9.00%
Level 3 [Member] | Liability [Member] | Income Approach [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount Rate, range (as a percentage)		3.26%
Level 3 [Member] | Liability [Member] | Income Approach [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount Rate, range (as a percentage)		3.26%
Level 3 [Member] | Liability [Member] | Income Approach [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount Rate, range (as a percentage)		3.26%