Debt (Secured Credit Facility Narrative) (Details) (USD $)	3 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Jul. 31, 2013
Debt Instrument [Line Items]
Loss on extinguishment of debt	$ (301,000)
Letters of credit outstanding	57,400,000		53,900,000
Ferrellgas, L.P. [Member]
Debt Instrument [Line Items]
Loss on extinguishment of debt	(301,000)
Letters of credit outstanding	57,400,000		53,900,000
Secured Credit Facility [Member]
Debt Instrument [Line Items]
Maturity date	Oct. 20, 2018
Secured credit facility maximum borrowing capacity	500,000,000.0		400,000,000.0
Total credit faciltiy borrowings outstanding	248,500,000		171,400,000
Amount of credit facility borrowings classified as long-term debt	133,400,000		121,300,000
Weighted average interest rate on credit facility borrowings	3.30%		3.70%
Secured Credit Facility [Member] | Ferrellgas, L.P. [Member]
Debt Instrument [Line Items]
Maturity date	Oct. 20, 2018
Secured credit facility maximum borrowing capacity	500,000,000.0		400,000,000.0
Total credit faciltiy borrowings outstanding	248,500,000		171,400,000
Amount of credit facility borrowings classified as long-term debt	133,400,000		121,300,000
Weighted average interest rate on credit facility borrowings	3.30%		3.70%
Letter Of Credit [Member]
Debt Instrument [Line Items]
Secured credit facility maximum borrowing capacity	200,000,000.0
Letter of credit remaining capacity	142,600,000		146,100,000
Letter Of Credit [Member] | Ferrellgas, L.P. [Member]
Debt Instrument [Line Items]
Secured credit facility maximum borrowing capacity	200,000,000.0
Letter of credit remaining capacity	$ 142,600,000		$ 146,100,000
Federal Funds Rate [Member] | Secured Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility interest rate basis spread rate	0.50%
Federal Funds Rate [Member] | Secured Credit Facility [Member] | Ferrellgas, L.P. [Member]
Debt Instrument [Line Items]
Credit facility interest rate basis spread rate	0.50%
Eurodollar Rate Loan [Member] | Secured Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility interest rate basis spread rate	1.00%
Eurodollar Rate Loan [Member] | Secured Credit Facility [Member] | Ferrellgas, L.P. [Member]
Debt Instrument [Line Items]
Credit facility interest rate basis spread rate	1.00%
Minimum [Member] | Base Rate [Member] | Secured Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility interest rate basis spread rate	0.75%
Minimum [Member] | Base Rate [Member] | Secured Credit Facility [Member] | Ferrellgas, L.P. [Member]
Debt Instrument [Line Items]
Credit facility interest rate basis spread rate	0.75%
Minimum [Member] | LIBOR [Member] | Secured Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility interest rate basis spread rate	1.75%
Minimum [Member] | LIBOR [Member] | Secured Credit Facility [Member] | Ferrellgas, L.P. [Member]
Debt Instrument [Line Items]
Credit facility interest rate basis spread rate	1.75%
Maximum [Member] | Base Rate [Member] | Secured Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility interest rate basis spread rate	1.75%
Maximum [Member] | Base Rate [Member] | Secured Credit Facility [Member] | Ferrellgas, L.P. [Member]
Debt Instrument [Line Items]
Credit facility interest rate basis spread rate	1.75%
Maximum [Member] | LIBOR [Member] | Secured Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility interest rate basis spread rate	2.75%
Maximum [Member] | LIBOR [Member] | Secured Credit Facility [Member] | Ferrellgas, L.P. [Member]
Debt Instrument [Line Items]
Credit facility interest rate basis spread rate	2.75%