Business combinations Business combinations (Aggregate Fair Value) (Details) - USD ($)
$ in Thousands
6 Months Ended 12 Months Ended
Jan. 31, 2016
Jul. 31, 2015
Goodwill, Acquired During Period $ 1,892  
Midstream - Crude Oil Logistics [Member]    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities (6,657)  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets   $ 1,783
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets (8,440)  
Postconfirmation, Goodwill 187,662  
Goodwill, Acquired During Period 1,892 193,311
Goodwill, Purchase Accounting Adjustments (5,649)  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets 2,375 2,375
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest 822,452 822,452
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred 0  
Transportation Equipment [Member] | Midstream - Crude Oil Logistics [Member]    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 293,491 293,491
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment 0  
Injection Stations and Pipelines [Member] | Midstream - Crude Oil Logistics [Member]    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 41,632 41,632
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment 0  
Office Equipment [Member] | Midstream - Crude Oil Logistics [Member]    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 7,449 7,449
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment 0  
Customer Lists [Member] | Midstream - Crude Oil Logistics [Member]    
Finite-lived Intangible Assets Acquired 277,100 261,811
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles 15,289  
Noncompete Agreements [Member] | Midstream - Crude Oil Logistics [Member]    
Finite-lived Intangible Assets Acquired 10,000 14,800
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles (4,800)  
Trademarks and Trade Names [Member] | Midstream - Crude Oil Logistics [Member]    
Indefinite-lived Intangible Assets Acquired 9,400 5,800
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles 3,600  
Other Noncurrent Assets [Member] | Midstream - Crude Oil Logistics [Member]    
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets 0  
Ferrellgas, L.P. [Member]    
Goodwill, Acquired During Period 1,892  
Ferrellgas, L.P. [Member] | Midstream - Crude Oil Logistics [Member]    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities (6,657)  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets   1,783
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets (8,440)  
Postconfirmation, Goodwill 187,662  
Goodwill, Acquired During Period 1,892 193,311
Goodwill, Purchase Accounting Adjustments (5,649)  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets 2,375 2,375
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest 822,452 822,452
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred 0  
Ferrellgas, L.P. [Member] | Transportation Equipment [Member] | Midstream - Crude Oil Logistics [Member]    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 293,491 293,491
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment 0  
Ferrellgas, L.P. [Member] | Injection Stations and Pipelines [Member] | Midstream - Crude Oil Logistics [Member]    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 41,632 41,632
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment 0  
Ferrellgas, L.P. [Member] | Office Equipment [Member] | Midstream - Crude Oil Logistics [Member]    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 7,449 7,449
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment 0  
Ferrellgas, L.P. [Member] | Customer Lists [Member] | Midstream - Crude Oil Logistics [Member]    
Finite-lived Intangible Assets Acquired 277,100 261,811
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles 15,289  
Ferrellgas, L.P. [Member] | Noncompete Agreements [Member] | Midstream - Crude Oil Logistics [Member]    
Finite-lived Intangible Assets Acquired 10,000 14,800
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles (4,800)  
Ferrellgas, L.P. [Member] | Trademarks and Trade Names [Member] | Midstream - Crude Oil Logistics [Member]    
Indefinite-lived Intangible Assets Acquired 9,400 $ 5,800
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles 3,600  
Ferrellgas, L.P. [Member] | Other Noncurrent Assets [Member] | Midstream - Crude Oil Logistics [Member]    
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets $ 0