v2.4.0.8
Intangible Assets (Narrative) (Details) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 6 Months Ended
Jun. 30, 2013
Jun. 30, 2012
Jun. 30, 2013
Jun. 30, 2012
Intangible Assets [Abstract]        
Costs incurred to acquire, develop and extend patents     $ 1,313 $ 389
Amortization expense for intangible assets 5,084 3,021 8,896 6,440
Annual estimated amortization expense, in 2013 11,034   11,034  
Annual estimated amortization expense, in 2014 18,613   18,613  
Annual estimated amortization expense, in 2015 16,756   16,756  
Annual estimated amortization expense, in 2016 14,889   14,889  
Annual estimated amortization expense, in 2017 $ 13,481   $ 13,481