Pensions and Other Post-retirement Benefits - Additional Information (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018
Retirement Benefits [Abstract]
Pension plans contributions	$ 3.5	$ 2.5
Total estimated pension plans contributions for the fiscal year	$ 7.1

Amount of contribution received by defined benefit plan from employer which increases plan assets.

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Name:	us-gaap_DefinedBenefitPlanContributionsByEmployer
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration