Employee Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Contribution Pension Plan [Line Items]
Defined Contribution Plan, Contributions Made to Benefit Plan	$ 2.4	$ 3.0	$ 3.5
First Tier of Employees Eligible Compensation Deferral
Defined Contribution Pension Plan [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent	100.00%
Employees Eligible Compensation Deferral, Percent	3.00%
Second Tier of Employees Eligible Compensation Deferral
Defined Contribution Pension Plan [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent	50.00%
Employees Eligible Compensation Deferral, Percent	2.00%