XML 57 R42.htm IDEA: XBRL DOCUMENT v3.20.4
Fair Value Measurements - Carrying Value and Estimated Fair Value of Long-term Debt, Including Current Maturities (Detail) - USD ($)
$ in Thousands
Dec. 31, 2020
Sep. 30, 2020
Fair Value Disclosures [Abstract]    
Long-term debt and finance leases, including current maturities, carrying value $ 746,398 $ 743,250
Long-term debt and finance leases, including current maturities, fair value $ 777,300 $ 768,700