Income Taxes (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Income Taxes
Effective income tax rate	36.60%	36.50%	36.60%	37.10%
Limitations on deductibility of excess annual employee compensation as mandated by health insurance reforms				$ 500,000