Component of Property and Equipment and their Estimated Useful Lives (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Sep. 30, 2015
Property, Plant and Equipment [Line Items]
Property and equipment	$ 184,079	$ 179,631
Less accumulated depreciation	113,669	111,508
Property and equipment, net	70,410	68,123
Land and land improvements
Property, Plant and Equipment [Line Items]
Property and equipment	17,645	17,054
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	32,203	31,288
Fleet and other equipment
Property, Plant and Equipment [Line Items]
Property and equipment	57,601	56,845
Tanks and equipment
Property, Plant and Equipment [Line Items]
Property and equipment	34,035	29,823
Furniture, fixtures and office equipment
Property, Plant and Equipment [Line Items]
Property and equipment	$ 42,595	$ 44,621