Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan.

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Amount of plan asset for defined benefit plan with accumulated benefit obligation in excess of plan assets.

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Amount of cost for defined contribution plan.

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Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

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Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans, classified as current.

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Retirement Plans - Textual (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Fair value of Pension Plan assets in excess of recorded liability	$ 19,000		$ 19,000
Maximum percent of participants' base compensation matched			6.00%
Employer total contribution amount	2,400	$ 2,000	$ 4,800	$ 4,800
Defined Benefit Pension Plans \| Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate for pension plan expense			4.32%
Defined Benefit Pension Plans \| Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Liability related to SERP plan	$ 333		$ 333