Segment and Geographic Data - Information about Reportable Segments (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
Operating income (loss)	96,155	$ 46,554	$ 79,803	$ 65,416	106,344	$ 95,729	$ 83,463	$ 62,177	287,928	347,713	304,586
Depreciation and amortization									83,818	82,383	44,523
Total assets	3,507,913				3,520,804				3,507,913	3,520,804
Dental [Member]
Segment Reporting Information [Line Items]
Net sales									2,390,219	2,476,234	2,415,003
Operating income (loss)									263,671	312,176	300,357
Depreciation and amortization									11,840	18,903	18,568
Total assets	863,970				994,113				863,970	994,113
Animal Health [Member]
Segment Reporting Information [Line Items]
Net sales									3,159,826	2,862,249	1,456,570
Operating income (loss)									88,132	94,318	56,670
Depreciation and amortization									50,144	44,243	8,861
Total assets	2,119,512				2,064,302				2,119,512	2,064,302
Corporate [Member]
Segment Reporting Information [Line Items]
Net sales									43,082	48,220	39,292
Operating income (loss)									(63,875)	(58,781)	(52,441)
Depreciation and amortization									21,834	19,237	$ 17,094
Total assets	$ 524,431				$ 462,389				$ 524,431	$ 462,389