Acquisitions - Summary of Unaudited Pro Forma Financial Result (Detail) - Animal Health International [Member] - USD ($) $ in Thousands |
9 Months Ended | |
|---|---|---|
Jan. 30, 2016 |
Jan. 24, 2015 |
|
| Business Acquisition [Line Items] | ||
| Pro forma net sales | $ 4,125,969 | $ 4,033,188 |
| Pro forma net income from continuing operations | $ 128,174 | $ 122,842 |