Stockholders' Equity - Narrative (Details) - USD ($) shares in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Feb. 28, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Oct. 31, 2013
Stockholders' Equity Note [Abstract]
Stock repurchase program, authorized amount						$ 750,000,000
Shares repurchased during period (in shares)				2.8
Repurchases of common stock	$ 62,000,000			$ 202,426,000	$ 226,513,000
Amortization expense from capitalized stock-based compensation		$ 2,900,000	$ 3,600,000	$ 9,300,000	$ 7,500,000