Shareholders' Equity - Treasury Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	May 02, 2012
Equity [Abstract]
Number of shares authorized to be repurchased			5,000,000
Stock Repurchased During Period, Shares	800,000
Payments for Repurchase of Common Stock	$ 4.9	$ 9.7
Remaining number of shares authorized to be repurchased	4,200,000
Average price per share of treasury stock acquired and held	$ 23.77
Movement in Treasury Stock [Roll Forward]
Balance as of December 31, 2011 (shares)	4,663,923
Purchases (shares)	840,170
Exercise of stock options (shares)	0
Restricted stock grants and other (shares)	(518,192)
401(k) matching contribution (shares)	(430,988)
Balance as of September 30, 2012 (shares)	4,554,913