Employee Benefits Employee Benefits (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Employee Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Short Term Incentive Plan Payout	$ 7.3	$ 7.4	$ 8.6
Defined Contribution Plans
Employee Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent	50.00%
Limits of Contribution Match of Employee Compensation, Percentage	6.00%
Defined Contribution Plan, Employer Contribution Amount	$ 1.7	$ 1.7	$ 1.6