Shareholders' Equity - Treasury Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	2 Months Ended	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012	Jun. 30, 2011	May 02, 2012
Equity [Abstract]
Number of shares authorized to be repurchased				5,000,000
Stock Repurchased During Period, Shares	400,000
Payments for Repurchase of Common Stock		$ 2.4	$ 6.8
Remaining number of shares authorized to be repurchased	4,600,000	4,600,000
Average price per share of treasury stock acquired and held		$ 25.16
Movement in Treasury Stock [Roll Forward]
Balance as of December 31, 2011 (shares)		4,663,923
Purchases (shares)		410,793
Exercise of stock options (shares)		0
Restricted stock grants and other (shares)		(509,259)
401(k) matching contribution (shares)		(337,718)
Balance as of June 30, 2012 (shares)	4,227,739	4,227,739