Estimated Cost of Providing Uncompensated Care (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Health Care Trust Fund [Line Items]
Estimated cost of providing uncompensated care	$ 172,959	$ 161,013	$ 177,189
Charity Care
Health Care Trust Fund [Line Items]
Estimated cost of providing uncompensated care	78,475	95,675	131,890
Uninsured Discounts
Health Care Trust Fund [Line Items]
Estimated cost of providing uncompensated care	$ 94,484	$ 65,338	$ 45,299