v2.3.0.15
Marketable Securities (Investments Available For Sale) (Details) (USD $)
In Thousands
Sep. 30, 2011
Dec. 31, 2010
Investment Available for Sale, Cost Amount$ 74,241$ 72,647
Investment Available for Sale, Gross Unrealized Gains4,3302,137
Investment Available for Sale, Gross Unrealized Losses(593)(14)
Investment Available for Sale, Fair Value77,97874,770
SEI-Sponsored Mutual Funds [Member]
  
Investment Available for Sale, Cost Amount8,7785,086
Investment Available for Sale, Gross Unrealized Gains67279
Investment Available for Sale, Gross Unrealized Losses(593)(14)
Investment Available for Sale, Fair Value8,2525,351
Other Mutual Funds [Member]
  
Investment Available for Sale, Cost Amount109443
Investment Available for Sale, Gross Unrealized Gains1359
Investment Available for Sale, Gross Unrealized Losses00
Investment Available for Sale, Fair Value122502
Debt Securities [Member]
  
Investment Available for Sale, Cost Amount65,35467,118
Investment Available for Sale, Gross Unrealized Gains4,2501,799
Investment Available for Sale, Gross Unrealized Losses00
Investment Available for Sale, Fair Value$ 69,604$ 68,917