Income Taxes - Differences Between Income Tax Provision (Benefit) and Income Taxes Computed using Applicable U.S. Statutory Federal Tax Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Income Tax Disclosure [Abstract]
Income tax provision computed at federal statutory rate	$ 6,177	$ (217)	$ (4,257)
State income taxes, net of federal benefit	243	(12)	(101)
Foreign income taxed at different rates	(938)	(596)	493
Dividends	(1,069)	(1,373)	115
Change in deferred tax asset valuation allowance	(36)	453	523
Reduction in uncertain tax positions	(1,207)	(1,236)	(1,022)
Nondeductible compensation	1,325	1,064	474
Tax credits generated	(1,741)	(704)	(2,002)
Travel and entertainment	314	220	124
Merger costs	228	187	251
Other	134	234	417
Income tax provision (benefit)	$ 3,430	$ (1,980)	$ (4,985)