Revenue - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue from External Customer [Line Items]
Changes in contract estimates related to projects in progress			$ 11.4	$ 10.8
Transferred over Time | Product Concentration Risk | Revenue from Contract with Customer Benchmark
Revenue from External Customer [Line Items]
Concentration risk, percentage	93.00%	95.00%	92.00%	95.00%
Transferred at Point in Time | Product Concentration Risk | Revenue from Contract with Customer Benchmark
Revenue from External Customer [Line Items]
Concentration risk, percentage	7.00%	5.00%	8.00%	5.00%