Commitments And Contingencies (Narrative) (Details)	12 Months Ended
Dec. 31, 2019 USD ($) claim shares
Cotter, Jr. Related Litigation Matters [Member]
Commitments And Contingencies [Line Items]
Settlement awarded \| $	$ 1,550,000
Legal fees \| $	5,900,000
Litigation expense \| $	$ 925,000
Employment Litigation [Member]
Commitments And Contingencies [Line Items]
Number of new claims filed \| claim	2
Class B [Member] \| Cotter Estate [Member] \| Cotter, Jr. Related Litigation Matters [Member]
Commitments And Contingencies [Line Items]
Shares held by estate \| shares	427,808
Voting stock percent	25.50%
Class B [Member] \| Cotter Trust [Member] \| Cotter, Jr. Related Litigation Matters [Member]
Commitments And Contingencies [Line Items]
Shares held by estate \| shares	696,080
Voting stock percent	41.40%
Class B [Member] \| Cotter Voting Trust [Member] \| Cotter, Jr. Related Litigation Matters [Member]
Commitments And Contingencies [Line Items]
Shares held by estate \| shares	1,123,888
Voting stock percent	66.90%

Commitments And Contingencies [Line Items]

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Common Stock, Shares Held in Estate

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Common Stock, Voting Stock Ownership Percent

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- Definition

The amount of expense provided in the period for legal costs incurred on or before the balance sheet date pertaining to resolved, pending or threatened litigation, including arbitration and mediation proceedings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.3)
-URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227

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- Definition

Amount awarded from other party in judgment or settlement of litigation.

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- Definition

Amount of litigation expense, including but not limited to legal, forensic, accounting, and investigative fees.

+ References

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- Definition

The total number of new claims filed pertaining to a loss contingency during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118942415&loc=d3e14435-108349

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