Segment and Geographic Data - Sales Information by Product (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 28, 2018	Jan. 27, 2018	Oct. 28, 2017	Jul. 29, 2017	Apr. 29, 2017	Jan. 28, 2017	Oct. 29, 2016	Jul. 30, 2016	Apr. 27, 2019	Apr. 28, 2018	Apr. 29, 2017
Segment Reporting Information [Line Items]
Net sales	$ 1,436,706	$ 1,396,745	$ 1,404,752	$ 1,336,320	$ 1,400,609	$ 1,375,222	$ 1,385,737	$ 1,304,115	$ 5,574,523	$ 5,465,683	$ 5,593,127
Consumable
Segment Reporting Information [Line Items]
Net sales									4,482,016	4,415,643	4,400,888
Equipment and software
Segment Reporting Information [Line Items]
Net sales									753,805	709,253	834,526
Other
Segment Reporting Information [Line Items]
Net sales									338,702	340,787	357,713
Dental net sales
Segment Reporting Information [Line Items]
Net sales									2,191,790	2,196,078	2,390,219
Dental net sales | Consumable
Segment Reporting Information [Line Items]
Net sales									1,214,814	1,251,642	1,321,764
Dental net sales | Equipment and software
Segment Reporting Information [Line Items]
Net sales									694,864	660,355	780,868
Dental net sales | Other
Segment Reporting Information [Line Items]
Net sales									282,112	284,081	287,587
Animal Health net sales
Segment Reporting Information [Line Items]
Net sales									3,354,528	3,242,564	3,159,826
Animal Health net sales | Consumable
Segment Reporting Information [Line Items]
Net sales									3,267,202	3,164,001	3,079,124
Animal Health net sales | Equipment and software
Segment Reporting Information [Line Items]
Net sales									58,941	48,898	53,658
Animal Health net sales | Other
Segment Reporting Information [Line Items]
Net sales									28,385	29,665	27,044
Corporate net sales
Segment Reporting Information [Line Items]
Net sales									28,205	27,041	43,082
Corporate net sales | Other
Segment Reporting Information [Line Items]
Net sales									$ 28,205	$ 27,041	$ 43,082