v2.4.0.6
Marketable Securities (Trading Securities) (Details) (USD $)
In Thousands, unless otherwise specified
6 Months Ended 12 Months Ended
Jun. 30, 2012
Dec. 31, 2011
Gain (Loss) on Investments [Line Items]    
Trading Securities, Cost $ 142,452 $ 149,627
Trading Securities, Gross Unrealized Gains 1,816 1,653
Trading Securities, Gross Unrealized Losses (91,015) (94,955)
Trading Securities, Fair Value 53,253 56,325
SIV Securities [Member]
   
Gain (Loss) on Investments [Line Items]    
Trading Securities, Cost 139,188 146,363
Trading Securities, Gross Unrealized Gains 0 0
Trading Securities, Gross Unrealized Losses (91,001) (94,955)
Trading Securities, Fair Value 48,187 51,408
LSV-Sponsored Mutual Funds [Member]
   
Gain (Loss) on Investments [Line Items]    
Trading Securities, Cost 2,049 2,049
Trading Securities, Gross Unrealized Gains 1,816 1,653
Trading Securities, Gross Unrealized Losses 0 0
Trading Securities, Fair Value 3,865 3,702
Other Investments [Member]
   
Gain (Loss) on Investments [Line Items]    
Trading Securities, Cost 1,215 1,215
Trading Securities, Gross Unrealized Gains 0 0
Trading Securities, Gross Unrealized Losses (14) 0
Trading Securities, Fair Value $ 1,201 $ 1,215