Product Warranties (Details) - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Movement in Standard and Extended Product Warranty Accrual, Increase (Decrease) [Roll Forward]
Balance at beginning of the period	$ 4,922
Balance at beginning of the period	2,332
Balance at end of the period	5,246
Balance at end of the period	1,600
Other Current Liabilities
Movement in Standard and Extended Product Warranty Accrual, Increase (Decrease) [Roll Forward]
Balance at beginning of the period	4,922	$ 8,907
Warranty provision for sales	2,496	4,134
Settlement of warranty claims	(3,243)	(4,896)
Amounts related to sale of the Memcor product line	795	0
Foreign currency translation and other	276	119
Balance at end of the period	5,246	8,264
Other Noncurrent Liabilities
Movement in Standard and Extended Product Warranty Accrual, Increase (Decrease) [Roll Forward]
Balance at beginning of the period	2,332	3,360
Warranty provision for sales	481	1,148
Settlement of warranty claims	(1,298)	(509)
Amounts related to sale of the Memcor product line	136	0
Foreign currency translation and other	(51)	(258)
Balance at end of the period	$ 1,600	$ 3,741