Share Repurchase Programs (Details) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended	3 Months Ended	9 Months Ended			3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012 December 2011 Anti-Dilutive Share Repurchase Program [Member]	Sep. 30, 2012 December 2011 Anti-Dilutive Share Repurchase Program [Member]	Sep. 30, 2011 December 2011 Anti-Dilutive Share Repurchase Program [Member]	Dec. 31, 2011 December 2011 Anti-Dilutive Share Repurchase Program [Member]	Sep. 30, 2012 December 2009 Anti-Dilutive Share Repurchase Program [Member]	Sep. 30, 2011 December 2009 Anti-Dilutive Share Repurchase Program [Member]	Dec. 31, 2009 December 2009 Anti-Dilutive Share Repurchase Program [Member]
Share Repurchase Programs (Textuals) [Abstract]
Maximum number of share repurchases authorization					2,000,000			2,000,000
Repurchased and retired shares		87,223	543,923	1,022,971		202,971
Aggregate cost of repurchased and retired	$ 26,343	$ 3,500	$ 26,300			$ 9,500	$ 51,400
Maximum period of discretionary share repurchase program								2 years