Acquisitions (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2011 years	Sep. 30, 2010 Centaur Services Limited [Member] years	Sep. 30, 2011 Nelson Laboratories [Member] years
Business Acquisition [Line Items]
Business Acquisition, Date of Acquisition Agreement		February 8, 2010	March 21, 2011
Business Acquisition, Cost of Acquired Entity, Purchase Price		$ 44,053	$ 7,000
Business Acquisition, Cost of Acquired Entity, Cash Paid		42,053
Business Acquisition, Cost of Acquired Entity, Transaction Costs		1,100
Business Acquisition Cost Of Acquired Entity Purchase Price Adjustment		1,868
Defined Benefit Plan, Business Combinations and Acquisitions, Benefit Obligation		2,047
Business Acquisition, Note Payable Assumed		$ 2,000
Finite-Lived Intangible Assets, Useful Life, Minimum (in years)	1	1
Finite-Lived Intangible Assets, Useful Life, Maximum (in years)	20	20	10
Business Acquisition, Description of Acquired Entity		Centaur is a supplier of animal health products to veterinarians in the United Kingdom. Centaur sells products to both the companion animal market and production animal market.	Nelson is a distributor of animal health products to over 1,100 veterinary practices
Business Acquisition Goodwill Tax Deductible Life			15