XML 42 R31.htm IDEA: XBRL DOCUMENT v3.20.2
Fair Value of Financial Assets and Liabilities - Additional Information (Detail) - USD ($)
9 Months Ended
Jun. 30, 2020
Jun. 30, 2019
Fair Value Disclosures [Abstract]    
Transfers between Level 1, Level 2 and Level 3 $ 0 $ 0