Annual report pursuant to Section 13 and 15(d)

Note 8. Stock-Based Compensation Fair Value Assumptions and ESPP (Details)

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Note 8. Stock-Based Compensation Fair Value Assumptions and ESPP (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
6 Months Ended 12 Months Ended
Jun. 30, 2010
Dec. 31, 2009
Dec. 31, 2008
Jun. 30, 2011
Jun. 30, 2010
Jun. 30, 2009
ESPP, Maximum Employee Subscription Rate       10.00%    
ESPP, Offering Period In Months     24 6   6
ESPP, Discounted Purchase Price Percentage 85.00% 95.00%       85.00%
ESPP, Discount from Market Price, Offering Date 15.00% 5.00%       15.00%
ESPP Activities [Abstract]            
Total Cash Received from Employees for the Issuance of Shares Under the ESPP       $ 30,085 $ 20,714 $ 30,306
Number of Shares Purchased by Employees through the ESPP       1,123,000 758,000 1,615,000
Tax Benefits Realized in Connection with the disqualifying Dispositions of Shares Purchased under the ESPP       $ 2,194 $ 994 $ 1,612
Weighted Average Fair Value Per Share Based on Black-Scholes Model       $ 7.41 $ 8.51 $ 11.06
Number of ESPP Shares Available for Future Issuance       3,500,000    
ESPP Share Replenishment in Period 2,000,000     2,000,000 2,000,000 2,000,000
ESPP Maximum Annual Share Replenishment       2,000,000    
Employee Stock Purchase Plan Member [Member]
           
ESPP, Fair Value Assumptions and Methodology [Abstract]            
Expected stock price volatility       38.00% 35.00% 41.00%
Risk free interest rate       0.20% 0.20% 1.80%
Dividend yield       3.10% 1.60% 1.40%
Expected life of options (in years)       0.5 0.5 1.3