Share Repurchases (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Share Repurchases [Line Items]
Purchase of common stock	$ 0	$ 200,055
January 2015 Authorization [Member]
Share Repurchases [Line Items]
Number of shares authorized to be repurchased	15,000,000
Shares repurchased	0	2,753,165
Average price per share for repurchased shares (in dollars per share)		$ 72.66
Remaining number of shares authorized to be repurchased	6,771,458
Purchase of common stock		$ 200,055