Consolidated Statements of Shareholders' Equity (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Stockholders' Equity [Abstract]
Cash & restricted stock dividends (in dollars per share)	$ 1.52	$ 1.32	$ 1.15
Foreign currency translation adjustment, tax	$ (0.1)	$ (0.1)	$ (0.2)
Change in pension benefits, tax		$ (0.5)