Employee Benefit Plans - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2019
SERPs
Defined Benefit Plan Disclosure [Line Items]
Contributions to benefit plan		$ 0.9
Estimated future contributions		0.3
SERP settlement charge	$ 2.0
Defined benefit plans
Defined Benefit Plan Disclosure [Line Items]
Contributions to benefit plan		13.8
Estimated future contributions		$ 4.8

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

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of contributions expected to be received by defined benefit plan from employer in fiscal year. Excludes contributions paid by employer in current fiscal year.

+ References

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- Definition

Amount of gain (loss) recognized in net periodic benefit (cost) credit from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk related to obligation and assets used to effect settlement.

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