Use of Estimates (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Use Of Estimates [Abstract]
Allowances for contractual adjustments	$ 280,582,000		$ 289,937,000
Allowances for accounts receivable	29,120,000		27,862,000
Bad debt expense included in other operating expenses	$ 5,208,000	$ 5,900,000