Share-Based Compensation Plans Share-Based Compensation Plans - Activity of Stock Options Exercisable and Outstanding (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract]
Exercisable and vested options at period end, shares under option	193
Exercisable and vested options at period end, remaining contractual life (in years)	3 years
Exercisable and vested options at period end, average exercise price per share	$ 36.04
Exercisable and vested options at period end, intrinsic value per share	$ 53.61	[1]
Exercisable and vested options at period end, aggregate intrinsic value	$ 10,358
Common Stock, Market Fair Value	$ 89.65

[1] Computed based upon the amount by which the fair market value of the Company’s common stock at December 31, 2013, of $89.65 per share exceeded the weighted average exercise price.