Segment and Geographic Data - Sales Information by Product (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 30, 2016	Jan. 30, 2016	Oct. 31, 2015	Aug. 01, 2015	Apr. 25, 2015	Jan. 24, 2015	Oct. 25, 2014	Jul. 26, 2014	Apr. 30, 2016	Apr. 25, 2015	Apr. 26, 2014
Segment Reporting Information [Line Items]
Net sales	$ 1,453,770	$ 1,400,853	$ 1,389,210	$ 1,142,870	$ 1,035,061	$ 958,628	$ 978,220	$ 938,956	$ 5,386,703	$ 3,910,865	$ 3,585,141
Consumable [Member]
Segment Reporting Information [Line Items]
Net sales									4,153,921	2,697,581	2,418,201
Equipment and software [Member]
Segment Reporting Information [Line Items]
Net sales									857,001	865,013	839,152
Other [Member]
Segment Reporting Information [Line Items]
Net sales									375,781	348,271	327,788
Operating Segments [Member] | Dental [Member]
Segment Reporting Information [Line Items]
Net sales									2,476,234	2,415,003	2,348,403
Operating Segments [Member] | Dental [Member] | Consumable [Member]
Segment Reporting Information [Line Items]
Net sales									1,378,886	1,319,407	1,285,459
Operating Segments [Member] | Dental [Member] | Equipment and software [Member]
Segment Reporting Information [Line Items]
Net sales									806,993	818,342	795,132
Operating Segments [Member] | Dental [Member] | Other [Member]
Segment Reporting Information [Line Items]
Net sales									290,355	277,254	267,812
Operating Segments [Member] | Animal Health [Member]
Segment Reporting Information [Line Items]
Net sales									2,862,249	1,456,570	1,203,045
Operating Segments [Member] | Animal Health [Member] | Consumable [Member]
Segment Reporting Information [Line Items]
Net sales									2,775,035	1,378,174	1,132,742
Operating Segments [Member] | Animal Health [Member] | Equipment and software [Member]
Segment Reporting Information [Line Items]
Net sales									50,008	46,671	44,020
Operating Segments [Member] | Animal Health [Member] | Other [Member]
Segment Reporting Information [Line Items]
Net sales									37,206	31,725	26,283
Operating Segments [Member] | Corporate [Member]
Segment Reporting Information [Line Items]
Net sales									48,220	39,292	33,693
Operating Segments [Member] | Corporate [Member] | Consumable [Member]
Segment Reporting Information [Line Items]
Net sales									0	0	0
Operating Segments [Member] | Corporate [Member] | Equipment and software [Member]
Segment Reporting Information [Line Items]
Net sales									0	0	0
Operating Segments [Member] | Corporate [Member] | Other [Member]
Segment Reporting Information [Line Items]
Net sales									$ 48,220	$ 39,292	$ 33,693