Derivatives and Hedging Activities - Additional Information (Details)	6 Months Ended
	Mar. 31, 2020
Minimum
Derivative [Line Items]
Derivative, maturities	1 year
Maximum
Derivative [Line Items]
Derivative, maturities	10 years
Weighted average
Derivative [Line Items]
Derivative, maturities	7 years 2 months 12 days