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

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Amount of decrease in accumulated postretirement benefit obligation from one-percentage-point decrease in assumed health care cost trend rate.

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Amount of cash outflow for pension benefit. Includes, but is not limited to, employer contribution to fund plan asset and payment to retiree. Excludes other postretirement benefit.

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Pension Plans And Other Postretirement Benefit Plans (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Other Operating Activities, Cash Flow Statement	$ (13,526)	$ 1,114	$ 1,860
Percentage point increases in accumulated postretirement benefit obligation	13,900
Percentage point increase in service and interest cost	800
Percentage point decrease in accumulated postretirement benefit obligation	10,700
Percentage point decrease in service and interest cost	600
Payment for Pension Benefits	22,000	22,000	$ 22,000
Pension Plan And SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions to defined benefit pension plan	22,000	22,000
Expected contributions to pension plan	22,000
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions to defined benefit pension plan	0	$ 0
Expected contributions to pension plan	$ 6,700
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target investment allocation	35.00%	37.00%
Equity Securities [Member] \| Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Target investment allocation	60.00%	60.00%
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target investment allocation	49.00%	45.00%
Debt Securities [Member] \| Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Target investment allocation	40.00%	40.00%