XML 86 R34.htm IDEA: XBRL DOCUMENT v2.4.0.6
Summary of significant accounting policies (Tables)
 12 Months Ended
Dec. 31, 2011
Summary of significant accounting policies [Abstract]  
Estimate useful life of property, plant and equipment by category
 Depreciation of plant and equipment is provided for by the straight-line method over the following estimated useful lives:
 
 
Buildings and improvements:
14 to 45 years
 
Machinery and equipment:
5 to 22 years
Carrying amount and fair value of debt
The following table provides the carrying amounts and approximate fair value (based the last available trading data) of our 8.0% senior notes due 2014 (the “8.0% Notes”), our 7.5% senior unsecured notes due 2014 (the “7.5% Notes”) and our 1.75% convertible senior notes due 2024 (the “1.75% Notes”).
 

   
December 31, 2011
  
December 31, 2010
 
   
Carrying amount
  
Fair value
  
Carrying amount
  
Fair value
 
              
8.0% Notes
 $246,909  $249,292  $245,927  $249,604 
7.5% Notes
  2,603   2,564   2,603   2,541 
1.75% Notes
  ––   -   45,483   46,588