Acquisitions (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Business Acquisition [Line Items]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares		473,389
Cash payment made for acquisitions	$ 5,328,000	$ 5,337,000	$ 1,900,000
Vetstreet [Member]
Business Acquisition [Line Items]
Percentage of Company acquired			100.00%
Payments to Acquire Businesses, Gross			146,400,000
Weighted average amortization period of identifiable intangible assets	9 years
Bright Heart [Member]
Business Acquisition [Line Items]
Amount of goodwill deducted for income tax purpose	38,800,000
Percentage of Company acquired			100.00%
Payments to Acquire Businesses, Gross			50,000,000
Weighted average amortization period of identifiable intangible assets	5 years
Number of Businesses Acquired	0	0	9
Pro forma [Member]
Business Acquisition [Line Items]
Acquisition related costs	869,000.000
Think Pets Inc [Member]
Business Acquisition [Line Items]
Amount of goodwill deducted for income tax purpose	821,000
Percentage of Company acquired		100.00%
Business Acquisition, Cash and equity interest issued		21,000,000
Payments to Acquire Businesses, Gross		21,000,000
business acquisition cash including acquired cash		10,500,000
Weighted average amortization period of identifiable intangible assets	8 years
AVC [Member]
Business Acquisition [Line Items]
Business Acquisition, Purchase Price in CAD		81,000,000
Amount of goodwill deducted for income tax purpose	362,000
US Annualized Revenue At Acquisition		95,000,000
Payments to Acquire Businesses, Gross		81,000,000
Annualized Revenue At Acquisition CAD		95,000,000
Weighted average amortization period of identifiable intangible assets	6 years
Number of Businesses Acquired	0	44	0
Acquisitions Excluding Bright Heart And Pet DRx [Member]
Business Acquisition [Line Items]
Amount of goodwill deducted for income tax purpose	$ 15,000,000	$ 60,400,000	$ 26,400,000
Number of Businesses Acquired	20	35	18
Noncompete Agreements [Member] | Vetstreet [Member]
Business Acquisition [Line Items]
Weighted average amortization period of identifiable intangible assets	2 years
Noncompete Agreements [Member] | AVC [Member]
Business Acquisition [Line Items]
Weighted average amortization period of identifiable intangible assets	3 years
Contracts [Member] | Vetstreet [Member]
Business Acquisition [Line Items]
Weighted average amortization period of identifiable intangible assets	8 years
Customer Relationships [Member] | Vetstreet [Member]
Business Acquisition [Line Items]
Weighted average amortization period of identifiable intangible assets	10 years
Customer Relationships [Member] | Think Pets Inc [Member]
Business Acquisition [Line Items]
Weighted average amortization period of identifiable intangible assets	9 years
Customer Relationships [Member] | AVC [Member]
Business Acquisition [Line Items]
Weighted average amortization period of identifiable intangible assets	5 years
Technology And Trademarks [Member] | Vetstreet [Member]
Business Acquisition [Line Items]
Weighted average amortization period of identifiable intangible assets	7 years
Technology And Trademarks [Member] | Think Pets Inc [Member]
Business Acquisition [Line Items]
Weighted average amortization period of identifiable intangible assets	4 years
Trademarks [Member] | Think Pets Inc [Member]
Business Acquisition [Line Items]
Weighted average amortization period of identifiable intangible assets	2 years
Trademarks [Member] | AVC [Member]
Business Acquisition [Line Items]
Weighted average amortization period of identifiable intangible assets	10 years