Changes in Stock (Details) - shares	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Class of Stock [Line Items]
Common stock, shares issued (in shares)	5,262,000	4,530,000	4,937,000	4,138,000
Common Stock Class A [Member]
Class of Stock [Line Items]
Common stock, shares issued (in shares)	4,261,005		3,935,581
Stock Issued During Period, Shares, New Issues	0	16,000
Stock issued for compensation	106,000	81,000
Acquisition of Class A shares	0	0
Treasury Stock, Shares, Acquired	325,000	392,000
Shares, Issued	53,864,000	53,742,000	53,758,000	53,170,000
Common Stock Class A [Member] | Stock Investment Plan
Class of Stock [Line Items]
Stock Issued During Period, Shares, New Issues	0	475,000
Common Stock Class B [Member]
Class of Stock [Line Items]
Common stock, shares issued (in shares)	1,001,714		1,001,714
Stock Issued During Period, Shares, New Issues	0	0
Stock issued for compensation	0	0
Acquisition of Class A shares	0	0
Shares, Issued	1,002,000	1,002,000	1,002,000	1,002,000
Common Stock Class B [Member] | Stock Investment Plan
Class of Stock [Line Items]
Stock Issued During Period, Shares, New Issues	0	0
Treasury Stock, Common [Member]
Class of Stock [Line Items]
Stock Issued During Period, Shares, New Issues	0	0
Stock issued for compensation	0	0
Treasury Stock, Common [Member] | Stock Investment Plan
Class of Stock [Line Items]
Stock Issued During Period, Shares, New Issues	0	0