Acquisitions - Summary of Acquisitions (Details)	12 Months Ended
	Dec. 31, 2015 Laboratory Hospital	Dec. 31, 2014 Laboratory Hospital	Dec. 31, 2013 Laboratory Hospital
Animal Hospital [Member]
Summary of acquisitions of animal hospitals and laboratories
Acquisitions | Hospital	55	47	20
Acquisitions, merged | Hospital	(7)	(4)	(2)
Sold, closed or merged | Hospital	(9)	(9)	(18)
Net increase | Hospital	39	34	0
Laboratories [Member]
Summary of acquisitions of animal hospitals and laboratories
Acquisitions | Laboratory	1	0	1
Acquisitions, merged | Laboratory	(1)	0	0
New facilities | Laboratory	1	3	0
Net increase | Laboratory	1	3	1