Summary of Revenues by Payor Type (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Health Care Organization Receivable And Revenue Disclosures [Line Items]
Revenues	$ 1,780,949	$ 1,764,516	$ 1,833,475	$ 1,675,967	$ 1,264,674	$ 1,228,918	$ 1,261,397	$ 1,272,610	$ 7,054,907	$ 5,027,599	$ 4,775,235
Medicare
Health Care Organization Receivable And Revenue Disclosures [Line Items]
Revenues									3,605,852	2,087,261	1,990,736
Medicaid
Health Care Organization Receivable And Revenue Disclosures [Line Items]
Revenues									817,713	601,645	541,614
Medicare Advantage
Health Care Organization Receivable And Revenue Disclosures [Line Items]
Revenues									530,012	374,431	363,520
Medicaid Managed
Health Care Organization Receivable And Revenue Disclosures [Line Items]
Revenues									207,900	127,707	83,347
Other Payor
Health Care Organization Receivable And Revenue Disclosures [Line Items]
Revenues									2,131,012	2,051,812	1,999,173
Amount Before Eliminations
Health Care Organization Receivable And Revenue Disclosures [Line Items]
Revenues									7,292,489	5,242,856	4,978,390
Eliminations
Health Care Organization Receivable And Revenue Disclosures [Line Items]
Revenues									$ (237,582)	$ (215,257)	$ (203,155)