Employee Benefit Plans - Stock Options (Details) (Stock Options, USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Stock Options
Options Outstanding
Options outstanding at January 1, 2012	5,336,929
Options outstanding, weighted average exercise price, beginning balance	$ 12.84
Options granted, shares	1,356,700
Options granted, weighted average exercise price	$ 10.03
Options exercised, shares	(171,681)
Options exercised, weighted average exercise price	$ 8.91
Options cancelled or forfeited, shares	(1,002,603)
Options cancelled or forfeited, weighted average exercise price	$ 15.55
Options outstanding at December 31, 2012	5,519,345	5,336,929
Options outstanding, weighted average exercise price, ending balance	$ 11.78	$ 12.84
Options outstanding, weighted average remaining contractual term (years)	5 years 9 months 25 days
Options outstanding, aggregate intrinsic value	$ 24.4
Options Vested and Expected to Vest [Abstract]
Vested or expected to vest at December 31, 2012, shares	2,212,243
Vested or expected to vest at December 31, 2012, weighted average exercise price	$ 10.82
Vested or expected to vest at December 31, 2012, weighted average remaining contractual term (years)	6 years 4 months 9 days
Vested or expected to vest at December 31, 2012, aggregate intrinsic value	11.1
Options - Additional Disclosures [Abstract]
Options exercisable at December 31, 2012, shares	2,606,395
Options exercisable at December 31, 2012, weighted average exercise price	$ 12.86
Options exercisable at December 31, 2012, weighted average remaining contractual term (years)	5 years 2 months 15 days
Options exercisable at December 31, 2012, aggregate intrinsic value	9.7
Weighted-average grant date fair value	$ 5.06	$ 6.65	$ 5.73
Total intrinsic value of options exercised	0.5	3.0	7.2
Net proceeds from exercise of stock options	1.5	3.7	10.9
Unamortized compensation costs	$ 16.2
Unamortized compensation costs period of recognition (years)	2 years