Investment Securities (Details) (USD $)
In Thousands, unless otherwise specified
Jun. 30, 2012
Dec. 31, 2011
Available-for-sale securities    
Cost $ 606 $ 606
Unrealized Gains 3 4
Unrealized Losses      
Fair Value 609 610
Trading Securities    
Fair Value 7,322 4,032
Total investment securities 7,931 4,642
US Treasury Note (0.375%, 9/30/2012) [Member]
   
Available-for-sale securities    
Cost 504 504
Unrealized Gains 2 2
Unrealized Losses      
Fair Value 506 506
US Treasury Note (1.75%, 1/31/2014) [Member]
   
Available-for-sale securities    
Cost 102 102
Unrealized Gains 1 2
Unrealized Losses      
Fair Value 103 104
Equity securities [Member]
   
Trading Securities    
Fair Value 5,744 2,656
Short -term securities [Member]
   
Trading Securities    
Fair Value 800 636
Managed mutual funds [Member]
   
Trading Securities    
Fair Value $ 778 $ 740