Annual report pursuant to Section 13 and 15(d)

Share-Based Compensation (Narrative) (Details)

v2.4.0.6
Share-Based Compensation (Narrative) (Details) (USD $)
12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Phantom shares vested 134,584 124,994  
Phantom Stock Plan [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Maximum number of shares of phantom stock available for awards 562,500    
Total liability for share awards $ 10,900,000 $ 7,200,000  
Compensation costs 4,200,000 4,400,000 1,300,000
Unrecognized compensation cost 2,900,000    
Director Phantom Stock Plan [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period, years one    
Phantom shares annual award $ 50,000 $ 30,000