Earnings Per Share (Narrative) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended		1 Months Ended	43 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Aug. 08, 2014 Subsequent Event [Member]	Aug. 08, 2014 Subsequent Event [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Common stock repurchased, shares	1,873	2,546	2,022	5,013	1,200	43,800
Common stock repurchased, average price per share	$ 148.21	$ 107.61	$ 148.21	$ 100.10	$ 151.00	$ 87.47
Common stock repurchased, value	$ 277,561	$ 273,946	$ 299,625	$ 501,838	$ 177,800	$ 3,800,000