Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Narrative (Details)

v3.20.2
Fair Value Measurements - Narrative (Details) - USD ($)
1 Months Ended 12 Months Ended
Aug. 31, 2020
Sep. 30, 2020
Sep. 30, 2019
Fair Value Disclosures [Abstract]      
Assets held for sale, fair value   $ 0 $ 0
MSP termination benefits payment $ 5,175,000 5,175,000  
Deferred retirement benefit   $ 0  
Estimated discount rate     4.08%