Shareholders' Equity (Narrative) (Details) (USD $)	3 Months Ended				9 Months Ended		3 Months Ended	9 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Share repurchase plan [Member]	Sep. 30, 2014 Shares withheld to pay taxes [Member]	Sep. 30, 2013 Shares withheld to pay taxes [Member]	Oct. 23, 2014 Subsequent Event [Member] Share repurchase plan [Member]
Class of Stock [Line Items]
Cash dividends declared (usd per share)	$ 0.05	$ 0.05	$ 0.05	$ 0.10	$ 0.15	$ 0.10
Dividends					$ 56,689,000	$ 38,462,000
Stock Repurchase Program, Authorized Amount							86,400,000
Stock Repurchase Program, Number of Shares Authorized to be Repurchased										750,000,000
Stock repurchases, shares							7,700,000
Payments for Repurchase of Common Stock					$ 155,140,000	$ 89,940,000	$ 147,800,000	$ 7,200,000	$ 6,900,000