Net Revenues and Accounts Receivable (Details 1) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Accounts receivable attributable to major payer sources of reimbursement
Gross Accounts Receivable	$ 263,543	$ 259,857
Less: Allowance for doubtful accounts	(8,615)	(8,777)
Net Accounts Receivable	254,928	251,080
Medicare [Member]
Accounts receivable attributable to major payer sources of reimbursement
Gross Accounts Receivable	197,273	192,541
Medicaid and Local Government [Member]
Accounts receivable attributable to major payer sources of reimbursement
Gross Accounts Receivable	31,991	31,259
Commercial Insurance and Other [Member]
Accounts receivable attributable to major payer sources of reimbursement
Gross Accounts Receivable	$ 34,279	$ 36,057