Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 4.7	$ 3.6
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)	14,296,989	14,109,255
Treasury stock, shares (in shares)	1,915,593	1,872,265