Segment Reporting - Information about Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended
	Aug. 01, 2015	Jul. 26, 2014	Apr. 25, 2015
Segment Reporting Information [Line Items]
Net sales	$ 1,142,870	$ 938,956
Operating income (loss) from continuing operations	62,177	65,996
Total assets, excluding assets held for sale	3,472,592		$ 2,193,565
Assets held for sale	767,062		754,141
Total assets	4,239,654		2,947,706
Corporate [Member]
Segment Reporting Information [Line Items]
Net sales	10,456	9,782
Operating income (loss) from continuing operations	(18,047)	(10,540)
Total assets, excluding assets held for sale	494,647		539,863
Dental [Member]
Segment Reporting Information [Line Items]
Net sales	575,117	542,874
Operating income (loss) from continuing operations	67,252	62,549
Total assets, excluding assets held for sale	920,035		1,022,257
Animal Health [Member]
Segment Reporting Information [Line Items]
Net sales	557,297	386,300
Operating income (loss) from continuing operations	12,972	$ 13,987
Total assets, excluding assets held for sale	$ 2,057,910		$ 631,445