Schedule I Parent Only Balance Sheets, Statements Of Earnings And Cash Flows (Statement Of Earnings) (Details) (USD $)	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Condensed Financial Statements, Captions [Line Items]
Operating expense	$ 401,727,000	$ 411,038,000	$ 409,014,000
Operating income	82,980,000	105,761,000	158,363,000
Interest expense	(93,254,000)	(101,885,000)	(101,284,000)
Loss on extinguishment of debt		(46,962,000)	(20,716,000)
Other income (expense), net	506,000	567,000	(1,108,000)
Income tax expense	1,128,000	1,241,000	1,916,000
Net earnings (loss)	(10,896,000)	(43,760,000)	33,339,000
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Equity in earnings (loss) of Ferrellgas, L.P.	5,533,000	(10,950,000)	61,731,000
Operating expense	(350,000)	(358,000)	(424,000)
Operating income	5,183,000	(11,308,000)	61,307,000
Interest expense	(16,127,000)	(21,811,000)	(24,498,000)
Loss on extinguishment of debt		(10,513,000)	(3,408,000)
Other income (expense), net	0	0	(666,000)
Income tax expense	(8,000)	(16,000)	(26,000)
Net earnings (loss)	$ (10,952,000)	$ (43,648,000)	$ 32,709,000