Stock-based Compensation - Schedule of Fair Value at the Date of Grant (Detail)	3 Months Ended
	Dec. 31, 2017 shares
Fiscal 2016 (2016 - 2018) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Minimum Shares	13,268
Target Shares	66,338
Maximum Shares	132,676
Fiscal 2017 (2017 - 2019) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Minimum Shares	10,437
Target Shares	52,185
Maximum Shares	104,370