Earnings Per Share (Details 2) - $ / shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share
Number of shares	46,798	22,497	47,865	22,497
Range of exercise prices, low end of range (in dollars per share)	$ 61.42	$ 61.49	$ 61.42	$ 61.49
Range of exercise prices, high end of range (in dollars per share)	$ 66.32	$ 66.32	$ 66.32	$ 66.32