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Employee Benefit Plans (Schedule of Change in Fair Value of Plan Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Pension Benefit Plan [Member]
Change in Fair Value of Plan Assets:
Beginning Balance	$ 80,380	$ 66,771
Actual Return on Plan Assets	8,289	12,753
Employer Contributions	3,400	3,677
Benefits Paid	(3,148)	(2,821)
Ending Balance	88,921	80,380
Funded Status	(26,940)	(20,511)
Other Benefits Plan [Member]
Change in Fair Value of Plan Assets:
Beginning Balance	40,613	34,622
Actual Return on Plan Assets	3,988	5,192
Employer Contributions	1,094	1,601
Benefits Paid	(803)	(802)
Ending Balance	44,892	40,613
Funded Status	$ (7,884)	$ (14,553)

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Change in Fair Value of Plan Assets:

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Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses.

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

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Amount of funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status.

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Amount of payment to participant under defined benefit plan which decreases plan assets. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.

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