Consolidated Balance Sheets (Parenthetical)		Dec. 31, 2017 $ / shares shares	Dec. 31, 2016 $ / shares shares
Statement of Financial Position [Abstract]
Preferred Stock, shares authorized (in shares)		500,000	500,000
Preferred Stock, shares issued (in shares)		0	0
Common Stock, stated value (in dollars per share) | $ / shares		$ 1	$ 1
Common Stock, shares authorized (in shares)	[1]	45,000,000	45,000,000
End of period shares outstanding (in shares)	[1]	22,934,403	22,904,157

[1] Share data has been adjusted to reflect a 3-for-2 stock split on April 21, 2017.