Insurance settlement - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
Jan. 31, 2015	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Insurance Receivable for Malpractice [Abstract]
Insurance settlement	$ 1,000	$ 0	$ 0	$ 1,000
Insurance claim, malpractice description		Claim made under its insurance policy covering, among other things, employee theft relating to misappropriation of funds by two now former employees over an eight year period beginning in 2006.

Description of insurance coverage used by the entity to manage the financial risk of malpractice claims (including general and professional liability). Disclosure may include a discussion of the entity's risk management policies, a description of the insurance arrangements (including type, coverage, coverage limits, deductible), description of the insurer, and whether the entity is self insured or retains significant self-insurance risk.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 954
-SubTopic 450
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6491354&loc=d3e6049-115624

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration