Uncompensated Care (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Health Care Trust Fund [Line Items]
Uncompensated care	$ 1,045,572	$ 955,748	$ 806,679
Uncompensated care, percentage	100.00%	100.00%	100.00%
Charity Care
Health Care Trust Fund [Line Items]
Uncompensated care	778,268	804,301	664,212
Uncompensated care, percentage	74.00%	84.00%	82.00%
Uninsured Discounts
Health Care Trust Fund [Line Items]
Uncompensated care	$ 267,304	$ 151,447	$ 142,467
Uncompensated care, percentage	26.00%	16.00%	18.00%