Condensed Financial Information of Registrant of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Condensed Income Statements, Captions [Line Items]
Revenues	$ 162,064	$ 218,194	$ 462,025	$ 319,055	$ 167,161	$ 245,604	$ 762,309	$ 499,217	$ 1,161,338	$ 1,674,291	$ 1,961,724
General and administrative expenses									23,366	25,908	22,592
Operating income	(29,606)	(2,955)	96,319	23,646	(61,182)	(10,073)	134,095	30,773	87,404	93,613	79,855
Net interest expense									(7,485)	(14,059)	(16,854)
Amortization of debt issuance costs									(1,247)	(1,818)	(1,602)
Loss on redemption of debt										(7,345)
Net loss before equity income	(31,923)	(4,993)	94,113	21,475	(72,428)	(13,970)	129,876	26,913	78,672	70,391	61,399
Net income	$ (19,095)	$ (3,238)	$ 55,209	$ 12,058	$ (45,326)	$ (8,359)	$ 75,687	$ 15,554	44,934	37,556	36,084
STAR GAS PARTNERS, L.P.
Condensed Income Statements, Captions [Line Items]
Revenues									0	0	0
General and administrative expenses									1,363	1,314	1,420
Operating income									(1,363)	(1,314)	(1,420)
Net interest expense										(10,342)	(11,206)
Amortization of debt issuance costs										(521)	(520)
Loss on redemption of debt										(7,345)
Net loss before equity income									(1,363)	(19,522)	(13,146)
Equity income of Star Petro Inc. and subs									46,297	57,078	49,230
Net income									$ 44,934	$ 37,556	$ 36,084