Earnings Per Share (Summary of Antidilutive Stock Options) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Earnings Per Share
Antidilutive stock options	784	[1]	1,035	[1]	1,182	[1]	1,213	[1]
Weighted-average exercise price	$ 96.38	[1]	$ 89.69	[1]	$ 93.57	[1]	$ 87.85	[1]

[1] See Note 8 for further discussion on the terms of the Company's share-based compensation plans.