Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
Aug. 31, 2018	Aug. 31, 2017
Fair Value Disclosures [Abstract]
Settlements of contingent consideration obligations	$ 4.6	$ 3.3

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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3213-108585

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