Shareholders' Equity (Details) (USD $) In Thousands, except Share data, unless otherwise specified	0 Months Ended				12 Months Ended
	Jul. 26, 2012	Apr. 25, 2012	Jan. 26, 2012	Oct. 27, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Oct. 31, 2011
Class of Stock [Line Items]
Stock Redeemed or Called During Period, Value							$ 80,200
Declared quarterly cash dividend	$ 0.09	$ 0.08	$ 0.08	$ 0.09
Stock Repurchase Program, Number of Shares Authorized to be Repurchased								2,000,000
Stock Repurchased During Period, Shares					0
Stock Issued During Period, Value, New Issues							229,129
Proceeds from Issuance of Common Stock					$ 0	$ 0	$ 229,129
Dividend Declared [Member]
Class of Stock [Line Items]
Declared quarterly cash dividend			$ 0.10
Special cash dividend payable	$ 0.21	$ 0.14	$ 0.29