Commitments and Contingencies - Additional Information (Detail) $ / shares in Units, € in Millions, $ in Millions	1 Months Ended	3 Months Ended						6 Months Ended		9 Months Ended	12 Months Ended
	Apr. 30, 2017 EUR (€)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 EUR (€)	Jun. 30, 2016 USD ($) site	Dec. 31, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2018 EUR (€) site	Jun. 30, 2018 USD ($)	Sep. 30, 2016 $ / shares	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jun. 30, 2018 USD ($) site	Oct. 31, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2014 mi	Apr. 11, 2014 mi	Sep. 30, 2003 mi
Loss Contingencies [Line Items]
Loss Contingency Accrual, Payments		$ 78.8	$ 350.0
Loss Contingency Accrual, Disclosures [Abstract]
Option Indexed to Issuer's Equity, Strike Price (in dollars per share) | $ / shares										$ 1
Option Indexed To Issuers Equity Settlement Alternatives Amount At Fair value		20.0									$ 20.0
Product Liability Contingency, Insurance Coverage [Abstract]
Loss Contingency Accrual Payments Future Interest Requirements													$ 1.2
Estimated Insurance Recoveries													25.0
Accrual for Environmental Loss Contingencies, Provision for New Losses			1.9		$ 1.1	$ 1.1
Accrual for Environmental Loss Contingencies		27.3									27.3		$ 25.3
Investigative Sites Notice From The EPA | site					6
Site Contingency, Focused Feasibility Study, Estimate of Cost, Low End of Range														$ 165.0
Site Contingency, Number of Sites Subject to Remediation Activities, Total | site								15					15
Loss Contingency, Estimate of Possible Loss | €								€ 0.4
Asbestos Issue [Member]
Loss Contingencies [Line Items]
Loss Contingency Accrual, Payments			$ 50.0
Product Liability Contingency, Insurance Coverage [Abstract]
Loss Contingency, Insurance Coverage, Amount													$ 32.1
Loss Contingency, Receivable													17.1
Estimated Insurance Recoveries													4.6
GST, LLC [Member] | Asbestos Issue [Member]
Product Liability Contingency, Insurance Coverage [Abstract]
Loss Contingency, Insurance Coverage, Amount Submitted for Reimbursement													15.0
Loss Contingency, Insurance Coverage, Amount Recovered, Insolvent Carrier													8.8
OldCo [Member]
Product Liability Contingency, Insurance Coverage [Abstract]
Loss Contingency, Insurance Coverage, Amount													15.0
New Coltec [Member]
Loss Contingency Accrual, Disclosures [Abstract]
Litigation Settlement, Amount Awarded to other third party											20.0
Minimum [Member]
Product Liability Contingency, Insurance Coverage [Abstract]
Site Contingency, Loss Exposure in Excess of Accrual, Best Estimate | €	€ 1.8			€ 5.1
Portion Of Site Subject To Remediation | mi																9	8
Maximum [Member]
Product Liability Contingency, Insurance Coverage [Abstract]
Site Contingency, Loss Exposure in Excess of Accrual, Best Estimate				€ 2.1			$ 1,730.0	€ 6.6	$ 1,380.0
Portion Of Site Subject To Remediation | mi																		17
New Coltec [Member]
Loss Contingency Accrual, Disclosures [Abstract]
Litigation Settlement, Amount Awarded to other third party		$ 60.0									40.0
Onondaga Site EPA Remedial Investigation [Domain]
Product Liability Contingency, Insurance Coverage [Abstract]
Accrual for Environmental Loss Contingencies, Provision for New Losses												$ 1.5
Coltec Industries Inc. [Member]
Product Liability Contingency, Insurance Coverage [Abstract]
Accrual for Environmental Loss Contingencies, Provision for New Losses											$ 5.7
Accrual for Environmental Loss Contingencies													$ 2.6		$ 1.3