Calculation of Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Calculation of Basic and Diluted Earnings per Share
Net income attributable to VCA Inc.	$ 51,093	$ 46,227
Weighted-average common shares outstanding:
Basic (in shares)	81,245,000	80,776,000
Effect of dilutive potential common shares:
Stock options (in shares)	360,000	284,000
Non-vested shares and units (in shares)	574,000	463,000
Diluted (in shares)	82,179,000	81,523,000
Basic earnings per share (in dollars per share)	$ 0.63	$ 0.57
Diluted earnings per share (in dollars per share)	$ 0.62	$ 0.57
Calculation of Earnings per Share (Textuals) [Abstract]
Potential common shares excluded from the computation of diluted earnings per share (in shares)	72,225	40,193