Incentive Stock Plans Summary of Restricted Shares (Details) (Restricted Stock [Member], USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted	33,607		18,742		20,535
Weighted average price of restricted shares granted	$ 57.54		$ 42.40		$ 43.55
Intrinsic value of restricted stock outstanding	$ 1.7	[1]	$ 2.1	[1]	$ 3.4	[1]
Fair value of restricted stock vested	1.3		1.8		2.6
Cash used to pay the minimum withholding tax requirements in lieu of receiving common shares	$ 0.3		$ 0.6		$ 0.8

[1] Intrinsic value of restricted stock outstanding is based on the market price of the Company’s stock at December 31, 2013.