Debt (Secured Credit Facility Narrative) (Details) (USD $)	6 Months Ended
	Jan. 31, 2014	Jul. 31, 2013	Jan. 31, 2013
Debt Instrument [Line Items]
Letters of credit outstanding	$ 60,300,000	$ 53,900,000
Ferrellgas, L.P. [Member]
Debt Instrument [Line Items]
Letters of credit outstanding	60,300,000	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
Write off of capitalized financing costs	300,000
Total credit faciltiy borrowings outstanding	207,500,000	171,400,000
Amount of credit facility borrowings classified as long-term debt	140,500,000	121,300,000
Weighted average interest rate on credit facility borrowings	3.40%	3.70%
Available borrowing capacity	232,200,000		177,900,000
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
Write off of capitalized financing costs	300,000
Total credit faciltiy borrowings outstanding	207,500,000	171,400,000
Amount of credit facility borrowings classified as long-term debt	140,500,000	121,300,000
Weighted average interest rate on credit facility borrowings	3.40%	3.70%
Available borrowing capacity	232,200,000		177,900,000
Letter Of Credit [Member]
Debt Instrument [Line Items]
Secured credit facility maximum borrowing capacity	200,000,000.0
Available borrowing capacity	139,700,000	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
Available borrowing capacity	$ 139,700,000	$ 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%