Income Taxes Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Tax Contingency [Line Items]
Statutory U.S. Federal tax rate	35.00%	35.00%	35.00%
State taxes - net of Federal benefit	3.10%	3.30%	3.10%
Other, net	0.00%	(0.10%)	(0.70%)
Effective tax rate	38.10%	38.20%	37.40%