Segment and Geographic Information - Additional Information (Detail)	Dec. 31, 2012
Segment Reporting Information [Line Items]
Number of owned and operated hospitals	162
December 31, 2012 [Member]
Segment Reporting Information [Line Items]
Number of geographically organized groups	3
December 31, 2012 [Member] | National Group [Member]
Segment Reporting Information [Line Items]
Number of owned and operated hospitals	63
December 31, 2012 [Member] | Southwest Group [Member]
Segment Reporting Information [Line Items]
Number of owned and operated hospitals	47
December 31, 2012 [Member] | Central Group [Member]
Segment Reporting Information [Line Items]
Number of owned and operated hospitals	46
December 31, 2012 [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Number of owned and operated hospitals	6
January 1, 2013 [Member] | National Group [Member]
Segment Reporting Information [Line Items]
Number of owned and operated hospitals	77
January 1, 2013 [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Number of owned and operated hospitals	6
January 1, 2013 [Member] | American Group [Member]
Segment Reporting Information [Line Items]
Number of owned and operated hospitals	79
Reorganization Group [Member] | January 1, 2013 [Member]
Segment Reporting Information [Line Items]
Number of geographically organized groups	2