Summary Of Significant Accounting Policies (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Summary Of Significant Accounting Policies [Line Items]
Number of states with service locations	48
Percentage of recognized income tax positions	50.00%
Costs of goods and services, allocation of related costs	$ 55,200,000	$ 53,700,000	$ 51,300,000
Retained earnings attributable to foreign subsidiaries	40,000
Sale items as a percentage of total revenues, approximate	44.00%	38.50%	36.70%
Salary and related expenses for pharmacists and other service professionals	11,100,000	10,700,000	11,800,000
Number of operating centers	1,100
Operating center, number of center managers	1
Operating center, number of customer service representatives	2
Salary and related expenses for service reps	113,400,000	108,900,000	104,600,000
Other salary and related costs, selling, general, and administrative	255,500,000	253,700,000	257,400,000
Salary and related expenses for respiratory therapists	$ 69,400,000	$ 68,400,000	$ 66,000,000
Lower percentage of fair market value of stock price to purchase company common stock under employee stock purchase plan	85.00%
Maximum percentage of base salary withheld on an after-tax basis for eligible employee	10.00%
Reserved	29,250,000
Shares issued under employee stock purchase plan	73,674	62,739	93,390
Shares issued under employee stock purchase plan	1,044,543
Number of operating centers providing home health care equipment and services	1,108
Shares issued, average price per share	$ 20.86	$ 20.49	$ 12.79
Approximate percentage of revenue as reimbursements from government sources	61.00%	60.00%	60.00%
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Operating center, approximate number of employees	7
Operating center, number of service representatives	2
Operating leases terms	1
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Operating center, approximate number of employees	8
Operating center, number of service representatives	3
Operating leases terms	5
Employee Stock Purchase Plan [Member]
Summary Of Significant Accounting Policies [Line Items]
Reserved	1,800,000