Basis of Presentation and Significant Accounting Policies (Summary of Portion of Medicaid Reimbursements Attributable to State Supplemental Payment Programs) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Health Care Organization Receivable And Revenue Disclosures [Line Items]
Medicaid revenues	$ 3,068,323	$ 3,080,653
Provider taxes and other expenses	526,614	528,460
State Supplemental Payment Programs [Member]
Health Care Organization Receivable And Revenue Disclosures [Line Items]
Medicaid revenues	45,297	52,215
Provider taxes and other expenses	16,893	19,426
Reimbursements attributable to state supplemental payment programs, net of expenses	$ 28,404	$ 32,789