Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Intangible assets, accumulated amortization	$ 16.9	$ 15.3
Intangible liabilities, accumulated amortization	$ 14.3	$ 13.5
Preferred stock, par value (in USD per share)	$ 1.00	$ 1.00
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	91,669
Preferred stock, shares outstanding	0	91,669
Common stock, par value (in USD per share)	$ 0.01	$ 2.50
Common stock, shares authorized	30,000,000	30,000,000
Common stock, shares issued	18,021,061	17,102,777
Common stock, shares outstanding	18,021,061	17,102,777