Supplemental Disclosure of Cash Flow Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Cash paid during the period for:
Income taxes, net	$ 22,570	$ 38,265	$ 25,518
Interest	$ 7,785	16,950	16,968
Non-cash investing activities:
Acquisition of NYC heating oil customer list		886
Non-cash financing activities:
Increase in interest expense-amortization of debt discount on 8.875% Senior Notes		$ 112	$ 112