Segment Reporting - Narrative (Detail) $ in Thousands	3 Months Ended	9 Months Ended
Jan. 28, 2017 USD ($)	Jan. 28, 2017 USD ($) Segment
Segment Reporting [Abstract]
Number of reportable segments \| Segment		3
Distribution Rights [Member] \| Dental [Member]
Segment Reporting Information [Line Items]
Non-cash impairment charge before tax \| $	$ 36,312	$ 36,312

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

No definition available.

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration