Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
Treasury stock, shares	5,062,347	4,980,247
Nonvoting Common Stock [Member]
Common Stock, par value per share	$ 1	$ 1
Common Stock, shares authorized	50,000	50,000
Common Stock, shares issued
Voting Common Stock [Member]
Common Stock, par value per share	$ 1	$ 1
Common Stock, shares authorized	40,000,000	40,000,000
Common Stock, shares issued	23,775,766	23,717,321
Common Stock, shares outstanding	18,713,419	18,737,074

Face amount or stated value per share of common stock.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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