Segment and Geographic Data - Information by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 25, 2020	Jan. 25, 2020	Oct. 26, 2019	Jul. 27, 2019	Apr. 27, 2019	Jan. 26, 2019	Oct. 27, 2018	Jul. 28, 2018	Apr. 25, 2020	Apr. 27, 2019	Apr. 28, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 1,286,461	$ 1,456,155	$ 1,418,744	$ 1,328,651	$ 1,436,706	$ 1,396,745	$ 1,404,752	$ 1,336,320	$ 5,490,011	$ 5,574,523	$ 5,465,683
Property and equipment, net	303,725				305,790				303,725	305,790
Assets	2,715,350				3,269,269				2,715,350	3,269,269
Dental net sales
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									2,101,922	2,191,790	2,196,078
Assets	704,216				641,721				704,216	641,721
Animal Health net sales
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									3,336,253	3,354,528	3,242,564
Assets	1,485,284				2,156,723				1,485,284	2,156,723
Corporate net sales
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									51,836	28,205	27,041
Assets	525,850				470,825				525,850	470,825
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									4,554,345	4,638,184	4,537,326
Property and equipment, net	294,169				295,381				294,169	295,381
United States | Dental net sales
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									1,900,539	1,989,875	1,985,398
United States | Animal Health net sales
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									2,601,970	2,620,104	2,524,887
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									608,320	597,953	583,057
Property and equipment, net	2,030				1,976				2,030	1,976
United Kingdom | Animal Health net sales
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									608,320	597,953	583,057
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									327,346	338,386	345,300
Property and equipment, net	$ 7,526				$ 8,433				7,526	8,433
Canada | Dental net sales
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									201,383	201,915	210,680
Canada | Animal Health net sales
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									$ 125,963	$ 136,471	$ 134,620