Stockholders' Equity - Narrative (Details) - USD ($) shares in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Feb. 28, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Feb. 29, 2016	Oct. 31, 2013
Class of Stock [Line Items]
Stock repurchase program, authorized amount						$ 1,000,000,000.0	$ 750,000,000.0
Repurchases of common stock	$ (62,000,000)			$ (294,867,000)	$ (202,426,000)
Amortization expense from capitalized stock-based compensation		$ 3,500,000	$ 2,900,000	$ 10,400,000	$ 9,300,000
Common Stock [Member]
Class of Stock [Line Items]
Shares repurchased during period (in shares)				5.7