Significant Accounting Policies (Details 1)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Percentage of net service revenue
Percentage of net service revenue	100.00%	100.00%	100.00%	100.00%
Medicare [Member]
Percentage of net service revenue
Percentage of net service revenue	77.80%	79.80%	78.10%	79.70%
Medicaid [Member]
Percentage of net service revenue
Percentage of net service revenue	1.90%	2.40%	2.00%	2.40%
Other [Member]
Percentage of net service revenue
Percentage of net service revenue	20.30%	17.80%	19.90%	17.90%