Acquisitions - Summary of Acquisitions (Details)	8 Months Ended	12 Months Ended
	Dec. 31, 2016 Hospital	Dec. 31, 2016 Laboratory Hospital	Dec. 31, 2015 Laboratory Hospital	Dec. 31, 2014 Laboratory Hospital	May 01, 2016
Acquisitions, excluding CAPNA in 2016
Summary of acquisitions of animal hospitals and laboratories
Acquisitions, excluding CAPNA in 2016		71	55	47
CAPNA
Summary of acquisitions of animal hospitals and laboratories
Acquisitions, excluding CAPNA in 2016	2	56	0	0
Percentage of Company acquired					80.00%
Animal Hospital
Summary of acquisitions of animal hospitals and laboratories
Acquisitions, merged		(3)	(7)	(4)
Sold, closed or merged		(11)	(9)	(9)
Net increase		113	39	34
Laboratories
Summary of acquisitions of animal hospitals and laboratories
Acquisitions, excluding CAPNA in 2016 | Laboratory		0	1	0
Acquisitions, merged | Laboratory		0	(1)	0
New facilities | Laboratory		1	1	3
Net increase | Laboratory		1	1	3