Summary of Significant Accounting Policies - Calculation of Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Calculation of Basic and Diluted Earnings per Share
Net income attributable to VCA Inc.	$ 40,688	$ 58,231	$ 64,050	$ 46,227	$ 63,595	$ 54,854	$ 54,299	$ 38,301	$ 209,196	$ 211,049	$ 135,438
Weighted average common shares outstanding:
Basic (in shares)									80,926	81,443	86,656
Effect of dilutive potential common stock:
Stock options (in shares)									270	330	302
Nonvested shares and units (in shares)									529	641	867
Diluted (in shares)									81,725	82,414	87,825
Basic earnings per common share (in dollars per share)	$ 0.50	$ 0.72	$ 0.79	$ 0.57	$ 0.79	$ 0.68	$ 0.66	$ 0.47	$ 2.59	$ 2.59	$ 1.56
Diluted earnings per common share (in dollars per share)	$ 0.50	$ 0.71	$ 0.78	$ 0.57	$ 0.78	$ 0.67	$ 0.65	$ 0.46	$ 2.56	$ 2.56	$ 1.54