Earnings Per Share, Textuals (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
	Jul. 01, 2015	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Potential dilutive effect of options and Warrants
Add: dilutive effect of warrants		744,000	778,000	0	596,000
Dividends
Cash dividends paid				$ 21.0	$ 19.1
Cash dividends paid per share				$ 1.20	$ 1.05
Treasury Stock, Number of Shares and Restriction Disclosures [Abstract]
Repurchase of common stock				599,397	410,589
Weighted-average price per share of common stock repurchased				$ 75.81	$ 70.34
Repurchase of common stock, total cost		$ 45.4		$ 45.4	$ 28.9
Common share amount available for additional share repurchase		$ 127.3		$ 127.3
Warrant Transactions
Potential dilutive effect of options and Warrants
Number of common shares underlying the Warrants outstanding		1,700,000	3,700,000	1,700,000	3,700,000	3,700,000
End of period incremental shares potentially issuable related to warrant exercises		473,850		473,850
Average exercise price of common shares underlying Warrants		$ 60.32	$ 60.80	$ 60.32	$ 60.80
Trading days warrants are exercisable	120 days
Issuance of stock warrants				516,220
Warrants exercised		2,000,000
Warrants [Member]
Potential dilutive effect of options and Warrants
Add: dilutive effect of warrants			778,147