Pension Plans (Contributions) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Qualified Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block
Contributions	$ 10,000	$ 0
Expected contributions during 2021	10,000
SERP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block
Contributions	534	$ 534
Expected contributions during 2021	$ 2,771

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

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Name:	us-gaap_DefinedBenefitPlanContributionsByEmployer
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration