Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	6 Months Ended
Nov. 30, 2017	Nov. 30, 2016
Fair Value Disclosures [Abstract]
Settlements of contingent consideration obligations	$ 3.3	$ 4.1

Cash outflow representing an adjustment to the purchase price of a previous acquisition.

No definition available.

Name:	us-gaap_PaymentsForPreviousAcquisition
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration