XML 48 R37.htm IDEA: XBRL DOCUMENT v3.21.1
Fair Value Measurements (Narrative) (Details) - USD ($)
Mar. 31, 2021
Sep. 30, 2020
Mar. 31, 2020
Sep. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Hedging collateral deposits $ 0 $ 0 $ 10,728,000 $ 6,832,000
Derivative Financial Instruments [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Level 3 Fair Value $ 0   $ 0