Debt (Secured Credit Facility Narrative) (Details) - USD ($)
$ in Millions |
Jan. 31, 2016 |
Jul. 31, 2015 |
| Debt Instrument [Line Items] |
|
|
| Letters of credit outstanding |
$ 72.0
|
$ 61.2
|
| Ferrellgas, L.P. [Member] |
|
|
| Debt Instrument [Line Items] |
|
|
| Letters of credit outstanding |
72.0
|
61.2
|
| Secured Credit Facility [Member] |
|
|
| Debt Instrument [Line Items] |
|
|
| Total credit faciltiy borrowings outstanding |
311.6
|
211.4
|
| Other Long-term Debt, Noncurrent |
$ 225.4
|
$ 136.1
|
| Weighted average interest rate on credit facility borrowings |
3.70%
|
3.50%
|
| Secured Credit Facility [Member] | Ferrellgas, L.P. [Member] |
|
|
| Debt Instrument [Line Items] |
|
|
| Total credit faciltiy borrowings outstanding |
$ 311.6
|
$ 211.4
|
| Other Long-term Debt, Noncurrent |
$ 225.4
|
$ 136.1
|
| Weighted average interest rate on credit facility borrowings |
3.70%
|
3.50%
|
| Letter Of Credit [Member] |
|
|
| Debt Instrument [Line Items] |
|
|
| Available borrowing capacity |
$ 128.0
|
$ 138.8
|
| Letter Of Credit [Member] | Ferrellgas, L.P. [Member] |
|
|
| Debt Instrument [Line Items] |
|
|
| Available borrowing capacity |
$ 128.0
|
$ 138.8
|