Shareholders' Equity - Treasury Stock (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended		38 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	May. 02, 2012
Equity [Abstract]
Number of shares authorized to be repurchased					5,000,000
Number shares repurchased	200,000	382,448		3,000,000
Payments for repurchase of common stock	$ 1.0	$ 1.7	$ 0.9	$ 13.3
Remaining number of shares authorized to be repurchased	2,000,000	2,000,000		2,000,000
Average price per share of treasury stock acquired and held				$ 13.23
Movement in Treasury Stock [Roll Forward]
Beginning balance (in shares)		627,796
Purchases (shares)	200,000	382,448		3,000,000
Exercise of stock options (in shares)		(12,381)
Restricted stock grants (in shares)		(690,662)
Forfeitures and other		863,743
Ending balance (in shares)	1,170,944	1,170,944		1,170,944