Quarterly report pursuant to Section 13 or 15(d)

Financial Instruments (Carrying amounts and fair value of the financial instruments) (Details)

v2.4.0.8
Financial Instruments (Carrying amounts and fair value of the financial instruments) (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2014
Dec. 31, 2013
Carrying Amount    
Current and long-term debt $ 1,047,706 $ 1,047,980
Fair Value    
Current and long-term debt $ 1,081,547 $ 1,058,431
Senior Notes Due 2021 [Member] | Line of Credit [Member]
   
Fair Value    
Debt percentage 6.75%  
Senior Notes Due 2019 [Member] | Line of Credit [Member]
   
Fair Value    
Debt percentage 8.63%