XML 26 R71.htm IDEA: XBRL DOCUMENT v2.4.0.6
Stock Buy Back Plans (Details) (USD $)
In Millions, except Share data, unless otherwise specified
 12 Months Ended 0 Months Ended 12 Months Ended
Dec. 31, 2011
Feb. 24, 2010
Class A Common Stock [Member]
Dec. 31, 2010
Class A Common Stock [Member]
Equity, Class of Treasury Stock [Line Items]      
Stock repurchase program, authorized amount   $ 30.0  
Stock repurchase program, expiration date March 31, 2011    
Number of shares purchased     784,197
Stock repurchased during period related to employee withholding upon vesting of restricted stock, shares 43,247    
Stock repurchased during period related to employee withholding upon vesting of restricted stock, value $ 1.5