Income Tax - Additional Information (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Sep. 30, 2018 USD ($) Year	Sep. 30, 2017 USD ($)	Jun. 30, 2018
Income Tax Examination [Line Items]
Income tax expense	$ 535	$ 759
Effective income tax rate	21.00%		35.00%
Tax cuts and jobs act 2017, measurement period from enactment date	1 year
Deferred tax	$ 0
Number of prior years with gross receipt eligible for BEAT minimum tax | Year	3
Minimum
Income Tax Examination [Line Items]
Average annual prior gross receipts treshhold amount for exemption from base erosion and anti abuse tax	$ 500,000
Foreign
Income Tax Examination [Line Items]
Income tax expense	$ 500	$ 800