CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015	Dec. 09, 2015	Dec. 31, 2014
Shares authorized for issuance of grants under equity compensation plan (in shares)			331,500
Common Stock [Member] | Common Shares Class A Non-Voting [Member]
Common stock, par value (in dollars per share)	$ 1.00
Common stock, shares authorized (in shares)	15,000,000	15,000,000		15,000,000
Common Stock Shares Issued	8,275,010	8,205,190		8,059,654
Shares available for purchase through retirement plans (in shares)	500,000
Shares authorized for issuance of grants under equity compensation plan (in shares)			331,500
Common Stock [Member] | Common Shares Class B Voting [Member]
Common stock, par value (in dollars per share)	$ 1.00
Common stock, shares authorized (in shares)	1,040,000	1,040,000		1,040,000
Common Stock Shares Issued	882,000	882,000		882,000