Organization and Summary of Accounting Policies - Schedule of Revenues by Sources (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenues	$ 496.1	$ 452.0	$ 1,311.8	$ 1,314.2
Total patient service revenues
Disaggregation of Revenue [Line Items]
Total revenues	$ 489.8	$ 444.5	$ 1,293.5	$ 1,294.8
Total patient service revenues | Customer | Revenue
Disaggregation of Revenue [Line Items]
Service revenues as a percentage of total revenues	100.00%	100.00%	100.00%	100.00%
Private insurance
Disaggregation of Revenue [Line Items]
Total revenues	$ 257.4	$ 236.3	$ 682.6	$ 682.1
Private insurance | Customer | Revenue
Disaggregation of Revenue [Line Items]
Service revenues as a percentage of total revenues	52.60%	53.20%	52.80%	52.70%
Government
Disaggregation of Revenue [Line Items]
Total revenues	$ 188.8	$ 175.4	$ 505.4	$ 518.4
Government | Customer | Revenue
Disaggregation of Revenue [Line Items]
Service revenues as a percentage of total revenues	38.50%	39.50%	39.10%	40.00%
Self-pay
Disaggregation of Revenue [Line Items]
Total revenues	$ 19.4	$ 11.8	$ 43.4	$ 32.1
Self-pay | Customer | Revenue
Disaggregation of Revenue [Line Items]
Service revenues as a percentage of total revenues	4.00%	2.70%	3.40%	2.50%
Other
Disaggregation of Revenue [Line Items]
Total revenues	$ 24.2	$ 21.0	$ 62.1	$ 62.2
Other | Customer | Revenue
Disaggregation of Revenue [Line Items]
Service revenues as a percentage of total revenues	4.90%	4.60%	4.70%	4.80%
Optical services revenues
Disaggregation of Revenue [Line Items]
Total revenues	$ 0.9	$ 0.9	$ 2.2	$ 3.0
Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	$ 5.4	$ 6.6	$ 16.1	$ 16.4