Retirement Plans - Additional Information (Details) $ in Millions	1 Months Ended		3 Months Ended		6 Months Ended
	Oct. 31, 2019 USD ($) Letter	Sep. 30, 2019 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Feb. 29, 2020 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Multiemployer Plans, Withdrawal Obligation		$ 237.2	$ 241.0		$ 241.0
Pension Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions by employer to pension and supplemental retirement plans			4.1	$ 5.5	12.6	$ 9.5
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions by employer to pension and supplemental retirement plans			$ 1.7	$ 1.7	$ 3.7	$ 4.4
Pace Industry Union Management Pension Fund [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Multiemployer Plans, Withdrawal Obligation	$ 2.3	170.3
Withdrawal obligation, per month		$ 0.7
Periods of Payments Used to Calculate Withdrawal Liability in Connection with PIUMPF Withdrawal	20 years	20 years
Number of additional demand letters | Letter	2
Withdrawal obligation accumulated funding deficiency	$ 2.0						$ 51.2