XML 55 R40.htm IDEA: XBRL DOCUMENT v3.21.2
Fair Value Measurements - Estimated Fair Value of Long-term Debt, Including Current Maturities (Detail) - USD ($)
$ in Thousands
Jun. 30, 2021
Sep. 30, 2020
Fair Value Disclosures [Abstract]    
Long-term debt and finance leases, including current maturities, carrying value $ 713,656 $ 743,250
Long-term debt and finance leases, including current maturities, fair value $ 724,800 $ 768,700