Leases - Lease Expenses (Details) - USD ($) $ in Thousands	3 Months Ended
	Oct. 31, 2020	Oct. 31, 2019
Lease, Cost [Abstract]
Operating lease expense	$ 9,033	$ 10,003
Short-term expense	2,275	2,064
Variable lease expense	1,134	1,408
Total finance lease expense	3,110	82
Total lease expense	15,552	13,557
Midstream Operations [Member]
Lease, Cost [Abstract]
Total lease expense	100	100
Operating expenses - personnel, vehicle, plant and other
Lease, Cost [Abstract]
Operating lease expense	1,783	1,741
Short-term expense	2,033	1,954
Variable lease expense	746	675
Operating expense - equipment lease expense
Lease, Cost [Abstract]
Operating lease expense	6,442	7,607
Variable lease expense	388	733
Cost of Sales [Member]
Lease, Cost [Abstract]
Operating lease expense	526	389
General and Administrative Expense [Member]
Lease, Cost [Abstract]
Operating lease expense	282	266
Short-term expense	242	110
Depreciation And Amortization Expense [Member]
Lease, Cost [Abstract]
Amortization of leased assets	2,165	40
Interest Expense [Member]
Lease, Cost [Abstract]
Interest on lease liabilities	945	42
Ferrellgas, L.P. [Member]
Lease, Cost [Abstract]
Operating lease expense	9,033	10,003
Short-term expense	2,275	2,064
Variable lease expense	1,134	1,408
Total finance lease expense	3,110	82
Total lease expense	15,552	13,557
Ferrellgas, L.P. [Member] | Midstream Operations [Member]
Lease, Cost [Abstract]
Total lease expense	100	100
Ferrellgas, L.P. [Member] | Operating expenses - personnel, vehicle, plant and other
Lease, Cost [Abstract]
Operating lease expense	1,783	1,741
Short-term expense	2,033	1,954
Variable lease expense	746	675
Ferrellgas, L.P. [Member] | Operating expense - equipment lease expense
Lease, Cost [Abstract]
Operating lease expense	6,442	7,607
Variable lease expense	388	733
Ferrellgas, L.P. [Member] | Cost of Sales [Member]
Lease, Cost [Abstract]
Operating lease expense	526	389
Ferrellgas, L.P. [Member] | General and Administrative Expense [Member]
Lease, Cost [Abstract]
Operating lease expense	282	266
Short-term expense	242	110
Ferrellgas, L.P. [Member] | Depreciation And Amortization Expense [Member]
Lease, Cost [Abstract]
Amortization of leased assets	2,165	40
Ferrellgas, L.P. [Member] | Interest Expense [Member]
Lease, Cost [Abstract]
Interest on lease liabilities	$ 945	$ 42