text: ***Accounts receivable:***Accounts receivable are recorded at the invoiced amount and do not bear interest. The 
  allowance for doubtful accounts is the Company’s best estimate of the amount of probable credit losses in the 
  Company’s existing accounts receivable. The Company determines the allowance based on historical write-off 
  experience and by industry and national economic data. The Company reviews its allowance for doubtful accounts 
  monthly. Past due balances meeting specific criteria are reviewed individually for collectibility. All other balances are 
  reviewed on a pooled basis. Account balances are charged off against the allowance after all means of collection have 
  been exhausted and the potential for recovery is considered remote. Accounts receivable are concentrated among 
  customers within the Company's geographic service area and large telecommunications companies. The Company's 
  allowance for uncollectable receivables related to continuing operations was $477 thousand, $914 thousand and $650 
  thousand at December 31, 2003, 2002 and 2001, respectively. 
  
  ***Securities and investments:***The classifications of debt and equity securities are determined by management at the date 
  individual investments are acquired. The appropriateness of such classification is continually reassessed. The 
  Company monitors the fair value of all investments, and based on factors such as market conditions, financial 
  information and industry conditions, the Company will reflect impairments in values as is warranted. The 
  classification of those securities and the related accounting policies are as follows: 