Contingencies - Warranty (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
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	$ 12,585	$ 14,583	$ 15,331	$ 18,091
Accruals for warranties issued	2,650	3,254	7,504	10,758
Changes in liability related to warranties existing in prior periods	157	711	(1,811)	(2,574)
Payments made	(3,155)	(3,258)	(8,787)	(10,985)
Balance at end of period	$ 12,237	$ 15,290	$ 12,237	$ 15,290