Benefit Plans - Unfunded Status (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Retirement Benefits [Abstract]
Projected benefit obligation	$ 52,142	$ 27,539	$ 30,877
Fair value of plan assets	42,866	20,254	$ 23,461
Underfunded status	9,276	7,285
Other post-retirement benefits income (loss)	(2,622)	$ 3,494
Expected amortization, next fiscal year	$ 200

No definition available.

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Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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Amount of cost (credit) included in accumulated other comprehensive (income) loss expected to be recognized in net periodic benefit cost (credit) for fiscal year following most recent annual statement of financial position.

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Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

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Amount, before tax, of gain (loss) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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

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