Schedule I Parent Only Balance Sheets, Statements Of Earnings And Cash Flows (Balance Sheets) (Details) - USD ($) $ in Thousands	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
ASSETS
Cash and cash equivalents	$ 11,054	$ 119,311	$ 5,760	$ 4,965
Prepaid expenses and other current assets	42,275	34,862
Other assets, net	69,105	74,588
Total assets	1,262,959	1,363,281
LIABILITIES AND PARTNERS' CAPITAL (DEFICIT)
Current portion of long-term debt	631,756	2,402
Other current liabilities	138,237	139,623
Long-term debt	1,457,004	2,078,637
Partners' capital (deficit)
Common unitholders	(1,046,245)	(978,503)
General partner unitholder	(70,476)	(69,792)
Accumulated other comprehensive income (loss)	(14,512)	20,510
Total Ferrellgas Partners, L.P. partners' deficit	(1,131,233)	(1,027,785)
Total liabilities and partners' capital (deficit)	$ 1,262,959	$ 1,363,281
Common unitholders, units outstanding	97,152,665	97,152,665
General partner unitholder, units outstanding	989,926	989,926
Parent Company [Member]
ASSETS
Cash and cash equivalents	$ 8	$ 3	59	75
Prepaid expenses and other current assets	57	23
Total assets	65	26
LIABILITIES AND PARTNERS' CAPITAL (DEFICIT)
Current portion of long-term debt	354,727
Other current liabilities	3,873	3,925
Long-term debt		350,500
Investment in Ferrellgas, L.P.	772,698	673,386
Partners' capital (deficit)
Common unitholders	(1,046,245)	(978,503)
General partner unitholder	(70,476)	(69,792)
Accumulated other comprehensive income (loss)	(14,512)	20,510
Total Ferrellgas Partners, L.P. partners' deficit	(1,131,233)	(1,027,785)
Total liabilities and partners' capital (deficit)	$ 65	26
Common unitholders, units outstanding	97,152,665
General partner unitholder, units outstanding	989,926
Parent Company [Member] | Reportable Legal Entities [Member]
ASSETS
Cash and cash equivalents	$ 11,045	119,133	$ 5,327	$ 4,472
Prepaid expenses and other current assets	42,158	34,050
Investment in Ferrellgas, L.P.	52,999	59,937
Other assets, net	65,447	63,411
Total assets	1,195,017	1,297,203
LIABILITIES AND PARTNERS' CAPITAL (DEFICIT)
Current portion of long-term debt	277,029	2,402
Other current liabilities	128,666	129,300
Long-term debt	1,457,004	1,728,137
Partners' capital (deficit)
Accumulated other comprehensive income (loss)	(14,647)	20,733
Total Ferrellgas Partners, L.P. partners' deficit	(780,403)	(680,078)
Total liabilities and partners' capital (deficit)	$ 1,195,017	$ 1,297,203