Quarterly report pursuant to Section 13 or 15(d)

Fair Value Disclosures (Details 1)

v2.4.0.8
Fair Value Disclosures (Details 1) (Level 2 [Member], USD $)
In Thousands, unless otherwise specified
Mar. 31, 2014
Dec. 31, 2013
4.50% senior notes due two thousand eighteen [Member]
   
Fair value of fixed-rate debt    
Aggregate Principal $ 175,000 $ 175,000
Estimated Fair Value 179,375 174,125
7.15% senior notes due 2020 [Member]
   
Fair value of fixed-rate debt    
Aggregate Principal 300,000 300,000
Estimated Fair Value 334,500 325,500
7.00% senior notes due 2022 [Member]
   
Fair value of fixed-rate debt    
Aggregate Principal 300,000 300,000
Estimated Fair Value 330,750 318,750
1.875% convertible senior notes due 2032 [Member]
   
Fair value of fixed-rate debt    
Aggregate Principal 126,500 126,500
Estimated Fair Value $ 133,774 $ 142,154