Revenue Recognition and Valuation Accounts - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Valuation and Qualifying Accounts [Abstract]
Allowance for doubtful accounts	$ 1.7		$ 1.7		$ 1.4
Allowance for contractual discounts	110.3		110.3		96.6
Allowance for uncompensated care	35.2		35.2		41.9
Value of uncompensated care to patients	2.3	$ 2.4	4.9	$ 4.8
Estimated cost of charity services	0.5	$ 0.7	$ 1.1	$ 1.3
Contractual period of services			3 years
Contract termination period			90 days
Termination fee			$ 13.5
Inventory valuation reserves	$ 14.3		$ 14.3		$ 13.5