Acquisitions (Details)	9 Months Ended
	Sep. 30, 2011 Hospital Year
Summary of acquisitions of animal hospitals and laboratories
Number of acquisitions, merged	(1)
Number of Properties Sold Closed or Merged	(6)
Animal Hospital Acquisitions [Member]
Summary of acquisitions of animal hospitals and laboratories
Number of Businesses Acquired	10
Bright Heart [Member]
Summary of acquisitions of animal hospitals and laboratories
Number of Businesses Acquired	9
Animal Hospitals Including Bright Heart [Member]
Summary of acquisitions of animal hospitals and laboratories
Number of Businesses Acquired	12
Laboratories Acquisitions [Member]
Summary of acquisitions of animal hospitals and laboratories
Number of Businesses Acquired	1
Laboratories Created [Member]
Summary of acquisitions of animal hospitals and laboratories
Number of Businesses Acquired	1
Laboratories [Member]
Summary of acquisitions of animal hospitals and laboratories
Number of Businesses Acquired	2