Debt - Borrowing Thresholds (Details)	12 Months Ended
	Sep. 30, 2016
Level I
Debt Instrument [Line Items]
Liquidity is less than at any time during the period	If Liquidity is less than $24,500 at any time during the period
Percentage Points	2.25 percentage points
Level II
Debt Instrument [Line Items]
Liquidity is greater than or equal to at all times and less than at any time.	If Liquidity is greater than or equal to $24,500 at all times during the period and less than $35,000 at any time during the period
Percentage Points	2.00 percentage points
Level III
Debt Instrument [Line Items]
Liquidity is greater than or equal to at all times during the period	If Liquidity is greater than or equal to $35,000 at all times during the period
Percentage Points	1.75 percentage points