General (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Concentration of Business
Net revenue	$ 773,213	$ 692,755
Maximum
Concentration of Business
Term of Contract (in years)	3
Term of renewed contract (in years)	2
Notice period for termination of contract (in days)	180
Minimum
Concentration of Business
Term of Contract (in years)	1
Term of renewed contract (in years)	1
Notice period for termination of contract (in days)	60
Pennsylvania Counties
Concentration of Business
Net revenue	92,300	84,600
Florida Areas
Concentration of Business
Net revenue	$ 34,100	$ 33,400