Component of Property and Equipment and their Estimated Useful Lives (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Sep. 30, 2014
Property, Plant and Equipment [Line Items]
Property and equipment	$ 179,631	$ 170,307
Less accumulated depreciation	111,508	102,888
Property and equipment, net	68,123	67,419
Land and land improvements
Property, Plant and Equipment [Line Items]
Property and equipment	17,054	16,884
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	31,288	30,877
Fleet and other equipment
Property, Plant and Equipment [Line Items]
Property and equipment	56,845	54,685
Tanks and equipment
Property, Plant and Equipment [Line Items]
Property and equipment	29,823	26,204
Furniture, fixtures and office equipment
Property, Plant and Equipment [Line Items]
Property and equipment	$ 44,621	$ 41,657