Stock-Based Compensation Weighted Average Assumptions (Details)	6 Months Ended
	Jun. 30, 2011 years payment
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected Dividend Yield	0.00%
Risk Free Interest Rate	2.01%	[1]
Expected Volatility	32.02%	[2]
Expected Life	5.5	[3]

[1] The risk-free interest rate for the periods within the contractual term of the options is based on the U.S. Treasury yield curve in effect at the time of the grant.

[2] The expected volatility is a measure of the amount by which a stock price has fluctuated or is expected to fluctuate based primarily on our and our peers' historical data.

[3] The expected life is the period of time, on average, that participants are expected to hold their options before exercise based primarily on  our historical data.