Schedule of Projected and Accumulated Benefit Obligations Rates (Detail)	Jun. 30, 2018	Jun. 30, 2017
Defined Benefit Pension Plans And Defined Benefit Postretirement Plans Disclosure [Abstract]
Discount rate	0.90%	0.80%
Salary increase rate	2.00%	2.00%

Weighted average rate increase of compensation, used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(2)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant