Calculation of Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Calculation of Basic and Diluted Earnings per Share
Net income attributable to VCA Inc.	$ 67,712	$ 64,050	$ 118,805	$ 110,277
Weighted-average common shares outstanding:
Basic (in shares)	81,267,000	80,835,000	81,256,000	80,806,000
Effect of dilutive potential common shares:
Stock options (in shares)	361,000	295,000	361,000	294,000
Non-vested shares and units (in shares)	600,000	599,000	587,000	530,000
Diluted (in shares)	82,228,000	81,729,000	82,204,000	81,630,000
Basic earnings per share (in dollars per share)	$ 0.83	$ 0.79	$ 1.46	$ 1.36
Diluted earnings per share (in dollars per share)	$ 0.82	$ 0.78	$ 1.45	$ 1.35
Calculation of Earnings per Share (Textuals) [Abstract]
Potential common shares excluded from the computation of diluted earnings per share (in shares)	58,359	21,122	68,938	24,047