Employee Benefit Plans (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Employee Benefit Plans [Abstract]
Retirement benefits based on years of service and compensation, years	5
Estimated net loss from defined benefit plan, that will be amortized into periodic costs	$ 4.0
Accumulated benefit obligation and the projected benefit obligation	46.6	42.2
Contribution expense under employee stock ownership plan	3.2	4.3	7.1
Shares allocated to the employee stock ownership plan	1.6	1.5	1.7
Defined contribution plans employee contribution percentage of eligible compensation matched by employer	6.00%
Contribution plan, employer matching contribution percentage	50.00%
Expected cash contribution to the pension plans in 2012	$ 0.5