Commitments And Contingencies (Details) - USD ($)		12 Months Ended
	Oct. 01, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Commitments And Contingencies [Line Items]
(Increase) decrease in prepaid and other assets		$ (2,122,000)	$ 1,307,000	$ 216,000
Cotter, Jr., Derivative Litigation [Member]
Commitments And Contingencies [Line Items]
Damages sought	$ 809,000
Class B [Member] | Cotter Estate [Member] | Cotter, Jr. Related Litigation Matters [Member]
Commitments And Contingencies [Line Items]
Shares held by estate		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		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		1,123,888
Voting stock percent		66.90%