Earnings Per Share (Narrative) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	1 Months Ended	3 Months Ended		9 Months Ended		22 Months Ended
	Nov. 08, 2012	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Nov. 08, 2012
Earnings Per Share
Common stock repurchased, shares	1,600	6,359	8,162	12,647	14,074	30,200
Common stock repurchased, average price per share	$ 83.68	$ 84.76	$ 61.51	$ 89.62	$ 59.69	$ 74.49
Common stock repurchased, value	$ 136,600	$ 538,972	$ 502,067	$ 1,133,328	$ 839,979	$ 2,200,000