Revenue Recognition and Valuation Accounts - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Valuation And Qualifying Accounts [Abstract]
Allowance for doubtful accounts	$ 1.1		$ 1.1		$ 1.0
Allowance for contractual discounts	97.6	66.7	97.6	66.7	74.7
Allowance for uncompensated care	38.8	45.3	38.8	45.3	46.4
Value of uncompensated care to patients	2.4	2.6	4.8	4.4
Estimated cost of charity services	0.7	1.0	1.3	1.7
Contractual period of services			3 years
Contract termination period			90 days
Termination fee			13.5
Inventory valuation reserves	$ 12.7		$ 12.7		$ 12.3