Leases - Lease Expenses (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jan. 31, 2020	Jan. 31, 2020
Lease, Cost [Abstract]
Operating lease expense	$ 10,841	$ 20,844
Short-term expense	2,153	4,217
Variable lease expense	824	2,232
Total finance lease expense	753	835
Total lease expense	14,571	28,128
Operating expenses - personnel, vehicle, plant and other
Lease, Cost [Abstract]
Operating lease expense	1,664	3,405
Short-term expense	2,012	3,966
Variable lease expense	671	1,346
Operating expense - equipment lease expense
Lease, Cost [Abstract]
Operating lease expense	8,156	15,763
Variable lease expense	153	886
Cost of Sales [Member]
Lease, Cost [Abstract]
Operating lease expense	324	713
General and Administrative Expense [Member]
Lease, Cost [Abstract]
Operating lease expense	697	963
Short-term expense	141	251
Depreciation And Amortization Expense [Member]
Lease, Cost [Abstract]
Amortization of leased assets	435	475
Interest Expense [Member]
Lease, Cost [Abstract]
Interest on lease liabilities	318	360
Ferrellgas, L.P. [Member]
Lease, Cost [Abstract]
Operating lease expense	10,841	20,844
Short-term expense	2,153	4,217
Variable lease expense	824	2,232
Total finance lease expense	753	835
Total lease expense	14,571	28,128
Ferrellgas, L.P. [Member] | Operating expenses - personnel, vehicle, plant and other
Lease, Cost [Abstract]
Operating lease expense	1,664	3,405
Short-term expense	2,012	3,966
Variable lease expense	671	1,346
Ferrellgas, L.P. [Member] | Operating expense - equipment lease expense
Lease, Cost [Abstract]
Operating lease expense	8,156	15,763
Variable lease expense	153	886
Ferrellgas, L.P. [Member] | Cost of Sales [Member]
Lease, Cost [Abstract]
Operating lease expense	324	713
Ferrellgas, L.P. [Member] | General and Administrative Expense [Member]
Lease, Cost [Abstract]
Operating lease expense	697	963
Short-term expense	141	251
Ferrellgas, L.P. [Member] | Depreciation And Amortization Expense [Member]
Lease, Cost [Abstract]
Amortization of leased assets	435	475
Ferrellgas, L.P. [Member] | Interest Expense [Member]
Lease, Cost [Abstract]
Interest on lease liabilities	$ 318	$ 360