Equity-Based Compensation - SARs Additional Information (Detail) - SARs - USD ($) $ / shares in Units, $ in Thousands	Sep. 30, 2016	Sep. 30, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of SARs exercisable (in shares)	456,082	492,473
SARs exercisable weighted average price (in dollars per share)	$ 10.69	$ 10.74
Number of SARs expected to vest (in shares)	26,575
Aggregate intrinsic value of SARs outstanding	$ 1,141	$ 1,900