Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 3.3	$ 4.1
Capital stock, par value (in dollars per share)	$ 1	$ 1
Serial preferred stock, shares authorized (in shares)	632,470	632,470
Serial preferred stock, shares issued (in shares)	0	0
Serial preferred stock, shares outstanding (in shares)	0	0
Common stock, shares authorized (in shares)	40,000,000	40,000,000
Common stock, shares issued (in shares)	14,653,985	14,513,821
Treasury stock, shares (in shares)	2,383,903	2,014,692