XML 89 R19.htm IDEA: XBRL DOCUMENT v2.4.0.8
Fair Value Measurements (Table)
6 Months Ended
Jun. 30, 2013
Fair Value Disclosures  
Fair value measurements
  Level within the Fair Value Hierarchy June 30, 2013 December 31, 2012
   Book Value  Fair Value Book Value Fair Value
(Dollars in thousands)             
Cash and cash equivalents1 $ 467,421 $ 467,421 $ 378,358 $ 378,358
Short-term investments             
 U.S. Treasury Notes1   110,352   110,352   100,676   100,676
Long-term investments             
 U.S. Treasury Notes1   40,120   40,141   50,305   50,339
Long-term debt             
 6.95% Senior Notes1   342,000   345,967   342,000   376,610
 6.7% Senior Notes2   532,319   529,204   532,194   582,744