Acquisitions Acquisitions - Schedule of Intangible Assets, other than goodwill (Details) $ in Millions	9 Months Ended
	Jun. 30, 2017 USD ($)
Business Acquisition [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	35.00%
Petmatrix LLC [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 37.8
Tradenames Trademarks And Patents [Member] | Petmatrix LLC [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 6.1
Customer Relationships [Member] | Petmatrix LLC [Member]
Business Acquisition [Line Items]
Business Acquisition Contingent Consideration Key Assumptions Discount Rate	12.00%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	35.00%
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 1.5
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Technology-Based Intangible Assets [Member] | Petmatrix LLC [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 30.2
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	13 years