Contingencies - Warranty (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Standard product warranty length, minimum	1 year
Standard product warranty length, maximum	2 years
Limited product warranty length (up to)	10 years
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 13,052	$ 13,388
Accruals for warranties issued	2,254	1,665
Changes in liability related to warranties existing in prior periods	377	67
Payments made	(3,067)	(2,474)
Balance at end of period	$ 12,616	$ 12,646