Debt (Secured Credit Facility Narrative) (Details) (Imported) (USD $) In Millions, unless otherwise specified	12 Months Ended					12 Months Ended								12 Months Ended					1 Months Ended																1 Months Ended	12 Months Ended		12 Months Ended		12 Months Ended
	Jul. 31, 2012 Letter Of Credit [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2011 Letter Of Credit [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2010 Letter Of Credit [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2012 Secured Credit Facility [Member]	Jul. 31, 2011 Secured Credit Facility [Member]	Jul. 31, 2012 Secured Credit Facility [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2012 Reductions from Previous Facility Rates [Member] Secured Credit Facility [Member]	Jul. 31, 2012 Reductions from Previous Facility Rates [Member] Secured Credit Facility [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2012 Federal Funds Rate [Member]	Jul. 31, 2011 Federal Funds Rate [Member]	Jul. 31, 2012 Federal Funds Rate [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2011 Federal Funds Rate [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2012 Federal Funds Rate [Member] Secured Credit Facility [Member]	Jul. 31, 2012 Eurodollar Rate Loan [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2012 Eurodollar Rate Loan [Member] Secured Credit Facility [Member]	Jul. 31, 2011 Eurodollar Rate Loan [Member] Secured Credit Facility [Member]	Jul. 31, 2012 Eurodollar Rate Loan [Member] Secured Credit Facility [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2011 Eurodollar Rate Loan [Member] Secured Credit Facility [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2012 Euro Rate [Member] Secured Credit Facility [Member]	Jul. 31, 2011 Euro Rate [Member] Secured Credit Facility [Member]	Jul. 31, 2012 Euro Rate [Member] Secured Credit Facility [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2011 Euro Rate [Member] Secured Credit Facility [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2012 Bank Of America's Prime Rate [Member]	Jul. 31, 2011 Bank Of America's Prime Rate [Member]	Jul. 31, 2012 Bank Of America's Prime Rate [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2011 Bank Of America's Prime Rate [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2012 One-Month Eurodollar Rate [Member]	Jul. 31, 2011 One-Month Eurodollar Rate [Member]	Jul. 31, 2012 One-Month Eurodollar Rate [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2011 One-Month Eurodollar Rate [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2012 Three-Month Eurodollar Rate [Member]	Jul. 31, 2011 Three-Month Eurodollar Rate [Member]	Jul. 31, 2012 Three-Month Eurodollar Rate [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2011 Three-Month Eurodollar Rate [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2012 Secured Credit Facility [Member]	Jul. 31, 2012 Secured Credit Facility [Member]	Jul. 31, 2011 Secured Credit Facility [Member]	Jul. 31, 2012 Secured Credit Facility [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2011 Secured Credit Facility [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2012 Secured Credit Facility [Member] Letter Of Credit [Member]	Jul. 31, 2011 Secured Credit Facility [Member] Letter Of Credit [Member]	Jul. 31, 2010 Secured Credit Facility [Member] Letter Of Credit [Member]	Jul. 31, 2012 Secured Credit Facility [Member] Letter Of Credit [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2011 Secured Credit Facility [Member] Letter Of Credit [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2012 Minimum [Member] Eurodollar Rate Loan [Member] Secured Credit Facility [Member]	Jul. 31, 2012 Minimum [Member] Eurodollar Rate Loan [Member] Secured Credit Facility [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2012 Minimum [Member] Euro Rate [Member] Secured Credit Facility [Member]	Jul. 31, 2012 Minimum [Member] Euro Rate [Member] Secured Credit Facility [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2012 Maximum [Member] Eurodollar Rate Loan [Member] Secured Credit Facility [Member]	Jul. 31, 2012 Maximum [Member] Eurodollar Rate Loan [Member] Secured Credit Facility [Member] Ferrellgas, L.P. [Member]	Jul. 31, 2012 Maximum [Member] Euro Rate [Member] Secured Credit Facility [Member]	Jul. 31, 2012 Maximum [Member] Euro Rate [Member] Secured Credit Facility [Member] Ferrellgas, L.P. [Member]
Line of credit facility maturity period				5 years
Secured line of credit facility																																			$ 400.0	$ 400.0		$ 400.0		$ 200.0			$ 200.0
Debt instrument, maturity date				September 2016		September 2016																														September 2016
Total borrowings outstanding, line of credit facility				160.0	129.5	160.0																																	129.5
Amount classified as long-term debt				64.3	64.6	64.3																																						64.6
Weighted average interest rate of debt																																			4.20%	4.20%	6.50%	4.20%	6.50%
Debt instrument, basis spread rate											0.50%		0.50%		3.00%	4.00%	3.00%	4.00%	2.00%	3.00%	2.00%	3.00%																							2.00%	2.00%	1.00%	1.00%	3.00%	3.00%	2.00%	2.00%
Debt instrument, base basis spread rate														1.00%					1.00%
Credit facility interest rate									0.13%	0.11%	0.13%	0.11%											3.25%	3.25%	3.25%	3.25%	0.31%	0.22%	0.31%	0.22%	0.43%	0.34%	0.43%	0.34%
Commitment fee payable rate																																			0.50%			0.50%
Letters of credit outstanding	64.5	47.5																																						64.5	47.5
Letter of credit facility, remaining capacity	135.5	152.5																																						135.5	152.5
Line of credit facility, commitment fee	$ 0.9	$ 1.1	$ 0.9																																					$ 0.9	$ 1.1	$ 0.9
Interest Rate, minimum							1.25%	1.25%
Interest Rate, maximum							1.50%	1.50%