Condensed Financial Information of Registrant Statements of Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Condensed Income Statements, Captions [Line Items]
Revenues	$ 222,362	$ 326,511	$ 892,241	$ 520,610	$ 177,608	$ 262,524	$ 785,139	$ 516,525	$ 1,961,724	$ 1,741,796	$ 1,497,588
General and administrative expenses									(22,592)	(18,356)	(18,689)
Operating income	(40,188)	(10,797)	93,953	36,887	(19,800)	(8,001)	75,229	18,577	79,855	66,005	58,259
Net interest expense									(16,854)	(14,433)	(14,060)
Amortization of debt issuance costs									(1,602)	(1,745)	(1,634)
Net loss before equity income	(44,115)	(16,618)	89,289	32,843	(23,686)	(11,952)	70,796	14,669	61,399	49,827	42,565
Net income	(25,828)	(9,592)	52,216	19,288	(13,937)	(7,588)	41,679	9,752	36,084	29,906	25,989
STAR GAS PARTNERS, L.P.
Condensed Income Statements, Captions [Line Items]
Revenues									0	0	0
General and administrative expenses									1,420	31	2,019
Operating income									(1,420)	(31)	(2,019)
Net interest expense									(11,206)	(11,197)	(11,188)
Amortization of debt issuance costs									(520)	(474)	(330)
Net loss before equity income									(13,146)	(11,702)	(13,537)
Equity income of Star Petro Inc. and subs									49,230	41,608	39,526
Net income									$ 36,084	$ 29,906	$ 25,989