Segment and Geographic Data - Sales Information by Product (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 29, 2017	Jan. 28, 2017	Oct. 29, 2016	Jul. 30, 2016	Apr. 30, 2016	Jan. 30, 2016	Oct. 31, 2015	Aug. 01, 2015	Apr. 29, 2017	Apr. 30, 2016	Apr. 25, 2015
Segment Reporting Information [Line Items]
Net sales	$ 1,445,032	$ 1,397,418	$ 1,418,241	$ 1,332,436	$ 1,453,770	$ 1,400,853	$ 1,389,210	$ 1,142,870	$ 5,593,127	$ 5,386,703	$ 3,910,865
Consumable [Member]
Segment Reporting Information [Line Items]
Net sales									4,400,888	4,153,921	2,697,581
Equipment and software [Member]
Segment Reporting Information [Line Items]
Net sales									834,526	857,001	865,013
Other [Member]
Segment Reporting Information [Line Items]
Net sales									357,713	375,781	348,271
Dental [Member]
Segment Reporting Information [Line Items]
Net sales									2,390,219	2,476,234	2,415,003
Dental [Member] | Consumable [Member]
Segment Reporting Information [Line Items]
Net sales									1,321,764	1,378,886	1,319,407
Dental [Member] | Equipment and software [Member]
Segment Reporting Information [Line Items]
Net sales									780,868	806,993	818,342
Dental [Member] | Other [Member]
Segment Reporting Information [Line Items]
Net sales									287,587	290,355	277,254
Animal Health [Member]
Segment Reporting Information [Line Items]
Net sales									3,159,826	2,862,249	1,456,570
Animal Health [Member] | Consumable [Member]
Segment Reporting Information [Line Items]
Net sales									3,079,124	2,775,035	1,378,174
Animal Health [Member] | Equipment and software [Member]
Segment Reporting Information [Line Items]
Net sales									53,658	50,008	46,671
Animal Health [Member] | Other [Member]
Segment Reporting Information [Line Items]
Net sales									27,044	37,206	31,725
Corporate [Member]
Segment Reporting Information [Line Items]
Net sales									43,082	48,220	39,292
Corporate [Member] | Other [Member]
Segment Reporting Information [Line Items]
Net sales									$ 43,082	$ 48,220	$ 39,292