Quarterly report pursuant to Section 13 or 15(d)

Business and Summary of Significant Accounting Principles (Narratives) (Details)

v2.4.0.6
Business and Summary of Significant Accounting Principles (Narratives) (Details) (USD $)
3 Months Ended 6 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Jun. 30, 2012
Jun. 30, 2011
Dec. 31, 2011
Business and Summary of Significant Accounting Policies [Abstract]          
Year Founded     1979    
Immaterial Error Correction     During the first quarter of 2012, we identified an error in the depreciable life of one fixed asset. The error resulted in a $146,000 quarterly or $585,000 annual understatement of depreciation expense in 2007 through 2010 and a corresponding overstatement of net property and equipment in service for the same periods. In the first and second quarters of 2011 the error resulted in a $146,000 quarterly understatement of depreciation expense and a corresponding overstatement of net property and equipment in service for the same periods. In the third and fourth quarters of 2011 the error resulted in a $49,000 quarterly overstatement of depreciation expense and a corresponding understatement of net property and equipment in service for the same periods. The net annual misstatement to 2011 was a $195,000 understatement to depreciation expense and a corresponding overstatement of net property and equipment in service for the same period. In order to assess materiality of this error we considered Staff Accounting Bulletin (“SAB”) 99, “Materiality” and SAB 108, “Considering the Effects of Prior Year Misstatements when Quantifying Misstatements in Current Year Financial Statements,” and determined that the impact of this error on prior period consolidated financial statements was immaterial. Although the error was and continues to be immaterial to prior periods, because of the significance of the out-of-period correction in the first quarter of 2012, we revised our prior period financial statements.    
Statement [Line Items]          
Revenues $ 176,104,000 $ 168,089,000 $ 348,011,000 $ 332,866,000  
Receivables 161,840,000   161,840,000   141,827,000
Class of Stock [Line Items]          
Stock Repurchased During Period, Value       21,100,000  
Stock Buyback Program [Member]
         
Class of Stock [Line Items]          
Stock Repurchase Program, Remaining Value Authorized to be Repurchased     93,900,000    
Common Stock - Class A [Member] | Stock Buyback Program [Member] | Number of shares repurchased [Member]
         
Class of Stock [Line Items]          
Stock Repurchased During Period, Shares 6,000 1,200,000 869,000 1,900,000  
Common Stock - Class A [Member] | Stock Buyback Program [Member] | Value of shares repurchased [Member]
         
Class of Stock [Line Items]          
Stock Repurchased During Period, Value 51,000 14,100,000 9,000,000 21,100,000  
Remote High Cost Support Program [Member]
         
Statement [Line Items]          
Receivables 31,700,000   31,700,000    
Urban High Cost Support Program [Member]
         
Statement [Line Items]          
Receivables 5,500,000   5,500,000    
Total High Cost Support Program [Member]
         
Statement [Line Items]          
Revenues $ 10,000,000 $ 13,700,000 $ 21,100,000 $ 26,000,000