Contingencies - Warranty (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 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	$ 12,058	$ 12,585	$ 13,388	$ 15,331
Accruals for warranties issued	2,798	2,650	7,170	7,504
Changes in liability related to warranties existing in prior periods	(285)	157	(1,369)	(1,811)
Payments made	(2,279)	(3,155)	(6,897)	(8,787)
Balance at end of period	$ 12,292	$ 12,237	$ 12,292	$ 12,237