Acquisitions Acquisition (Details) (USD $)	3 Months Ended		6 Months Ended				12 Months Ended	6 Months Ended				12 Months Ended			12 Months Ended	6 Months Ended				12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 AVC Acquisition [Member] Hospital	Jun. 30, 2012 AVC Acquisition [Member] Hospital	Dec. 31, 2012 AVC Acquisition [Member] Hospital	Jun. 30, 2013 Animal Hospital [Member] Hospital	Jun. 30, 2012 Animal Hospital [Member] Hospital	Jun. 30, 2013 Animal Hospitals And Laboratory Acquisitions [Member]	Jun. 30, 2012 Animal Hospitals And Laboratory Acquisitions [Member]	Dec. 31, 2012 AVC [Member]	Dec. 31, 2012 ThinkPetsAcquisition [Member]	Jun. 30, 2013 ThinkPetsAcquisition [Member]	Dec. 31, 2012 Think Pets Inc [Member]	Jun. 30, 2013 Laboratories Acquisitions [Member] Laboratory	Jun. 30, 2012 Laboratories Acquisitions [Member] Laboratory	Jun. 30, 2013 Laboratory [Member] Hospital	Jun. 30, 2012 Laboratory [Member] Hospital	Dec. 31, 2012 Customer Relationships [Member] AVC [Member]	Dec. 31, 2012 Customer Relationships [Member] Think Pets Inc [Member]	Dec. 31, 2012 Technology And Trademarks [Member] Think Pets Inc [Member]	Dec. 31, 2012 Trademarks [Member] AVC [Member]	Dec. 31, 2012 Trademarks [Member] Think Pets Inc [Member]	Dec. 31, 2012 Noncompete Agreements [Member] AVC [Member]
Business Acquisition Summary Of Acquired Properties [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life												6 years			8 years					5 years	9 years	4 years	10 years	2 years	3 years
Number of Businesses Acquired					0	44	44	6	14							1	0
Number Of Laboratories Created																0	1
Change In Number Of Laboratories Owned During The Period																		1	1
Annualized Revenue At Acquisition CAD							$ 95,000,000
Business Acquisition, Purchase Price Allocation, Goodwill, Expected Tax Deductible Amount					362,000					20,200,000	11,800,000			821,000
Payments (Less Than $1M) To Acquire Real Estate For Use by Owner	510,000
Preliminary Purchase Price CAD							81,000,000
Business Acquisition, Cost of Acquired Entity, Cash Paid	21,835,000	75,328,000	21,835,000	75,328,000			48,819,000	17.2					7,468,000
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned													10,500,000
Business Acquisition Cost Of Acquired Entity Cash Paid For Hold Backs													1,050,000
Business Acquisition, Contingent Consideration, at Fair Value	(46,000)	0	(46,000)	0
Business Combination, Consideration Transferred							74,734,000			22,341,000	19,668,000		19,018,000
Business Acquisition, Purchase Price Allocation, Tangible Assets							11,694,000						2,093,000
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets							25,170,000						7,221,000
Business Acquisition, Purchase Price Allocation, Goodwill Amount							79,707,000						12,155,000
Business Acquisition, Purchase Price Allocation, Liabilities Assumed							(21,826,000)			(532,000)	0		(2,451,000)
business acquisition purchase price allocation total							94,745,000
Redeemable Noncontrolling Interest Added Through Acquisitions			3,600,000							(3,600,000)
Noncontrolling Interest, Increase from Business Combination		(8,161,000)		(8,161,000)			(8,161,000)
Business Combination, Step Acquisition, Equity Interest in Acquiree, Fair Value	0	(11,850,000)	0	(11,850,000)			(11,850,000)
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net							74,734,000						19,018,000
Business Acquisitions Cash Paid To Debtholders							25,915,000
Business Acquisition, Percentage of Voting Interests Acquired								90.00%					100.00%
Business Acquisition Cost Of Acquired Entity Preliminary Purchase Price												81,000,000	21,000,000
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares													473,389
business acquisition cash including acquired cash													10,500,000
Number Of Acquired Hospitals Relocated To Existing Hospitals								(1)	(3)
Number Of Properties Sold Closed Or Merged								(9)	(4)
Change In Number Of Animal Hospitals Owned During The Period								(4)	51
US Annualized Revenue At Acquisition							$ 95,000,000