Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income tax provisions	$ 1,727,000	$ 1,152,000
Effective tax rates	42.90%	30.30%
U.S. federal statutory tax rate	35.00%	35.00%
Unrecognized tax benefits excluding interest and penalties that would impact effective tax rate	$ 1,200,000		$ 1,200,000
Undistributed earnings in foreign subsidiaries	$ 0		$ 0