General (Detail) - Entity [Domain] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Organization And Description Of Business [Line Items]
Revenue from Medicaid programs	$ 2,452,680	$ 2,227,721	$ 4,832,781	$ 4,374,219
Increase (decrease) in net revenue		32,000
Increase (decrease) in other operating expense				50,000
State Medicaid programs
Organization And Description Of Business [Line Items]
Revenue from Medicaid programs	92,000	75,000	159,000	124,000
Revenue offset amount	$ 39,000	$ 32,000	$ 67,000	$ 50,000