Fair Value Measurements - Schedule of Contingent Consideration Liabilities Measured at Fair Value (Detail) - Contingent Consideration [Member] - Significant Unobservable Inputs (Level 3) [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 13,870	$ 13,646	$ 14,517
Additions				$ 12,581
Fair value adjustments	(1,192)	70	(2,350)	70
Interest accretion	563	485	1,547	986
Foreign currency translation loss (gain)	600	(251)	127	313
Ending balance	$ 13,841	$ 13,950	$ 13,841	$ 13,950