Shareholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2015	Jun. 30, 2014
Class of Stock [Line Items]
Cash dividends declared (usd per share)	$ 0.08	$ 0.08	$ 0.05	$ 0.05	$ 0.16	$ 0.1
Dividends					$ 58,227	$ 37,979
Payments for repurchase of common stock					$ 322,066	$ 103,711
Share repurchase plan
Class of Stock [Line Items]
Share repurchases (shares)					15.3	5.0
Payments for repurchase of common stock					$ 313,000	$ 97,600
Remaining value of stock repurchase programs authorization	$ 425,400				425,400
Shares withheld to pay taxes
Class of Stock [Line Items]
Payments for repurchase of common stock					$ 9,000	$ 6,100