XML 41 R22.htm IDEA: XBRL DOCUMENT v2.4.0.6
Fair Value Measurements (Tables)
6 Months Ended
Jun. 30, 2012
Fair Value Measurements  
Valuation of senior notes

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

June 30, 2012

 

December 31, 2011

 

Carrying Amount

 

Estimated Fair Value

 

Carrying Amount

 

Estimated Fair Value

4.875% Senior Notes due 2021

$

 496,998

 

$

 529,450

 

$

 496,824

 

$

 533,150

4.625% Senior Notes due 2021

$

 299,519

 

$

 315,360

 

$

 299,493

 

$

 313,830