Shareholders' Equity (Stock Options) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Unrecognized compensation cost	$ 18.6
Weighted average period costs expected to be recognized (in years)	3 years 22 days
Stock Options and Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value of Stock options & SARs (in dollars per share)	$ 10.07	$ 8.61	$ 11.37
Expected stock price volatility (percent)	27.63%	26.88%	25.96%
Risk-free interest rate (percent)	2.11%	1.45%	1.49%
Expected annual dividend yield (percent)	1.87%	2.10%	1.55%
Expected term of option & SARs (in years)	5 years 9 months 26 days	5 years 11 months 26 days	5 years 8 months 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of shares outstanding, Beginning Balance	1,753
Number of shares, Granted	848
Number of shares, Forfeited	(148)
Number of shares, Exercised	(145)
Number of shares outstanding, Ending Balance	2,308	1,753
Number of shares, Exercisable	504
Number of shares, Stock options & SARs expected to vest	1,804
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted average exercise price, Beginning Balance (in dollars per share)	$ 42.16
Weighted average exercise price, Granted (in dollars per share)	42.30
Weighted average exercise price, Forfeited (in dollars per share)	44.49
Weighted average exercise price, Exercised (in dollars per share)	31.12
Weighted average exercise price, Ending Balance (in dollars per share)	42.75	$ 42.16
Exercisable, Weighted Average Exercise Price (in dollars per share)	42.46
Stock options & SARs expected to vest, Weighted Average Exercise Price (in dollars per share)	$ 42.83
Weighted average remaining contractual term, options outstanding (in years)	8 years 1 month 16 days
Weighted average remaining contractual term, options exercisable (in years)	6 years 11 months 24 days
Aggregate intrinsic value, options outstanding	$ 19.3
Aggregate intrinsic value, options exercisable	4.4
Aggregate intrinsic value	$ 2.7	$ 1.4	$ 2.8
Restricted Stock Units (RSUs) and Performance Share Units (PSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of shares outstanding, Beginning Balance	297
Number of shares, Granted	29
Number of shares, Vested	(84)
Number of shares, Forfeited	(14)
Number of shares outstanding, Ending Balance	228	297
Share-based Compensation Arrangement by Share-based Payment Award, Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted average grant date fair value, Beginning Balance (in dollars per share)	$ 41.01
Weighted average grant date fair value, Granted (in dollars per share)	48.32	$ 40.27	$ 45.75
Weighted average grant date fair value, Vested (in dollars per share)	41.06
Weighted average grant date fair value, Forfeited (in dollars per share)	44.64
Weighted average grant date fair value, Ending Balance (in dollars per share)	$ 41.66	$ 41.01
Total fair value of shares vested	$ 3.4	$ 4.7	$ 6.0