Variable Interest Entities and Consolidation of Investment Vehicles (Details 8) (CIVs, USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Mar. 31, 2013
CIVs
Debt Instrument
Fair Value Option, Gain (Loss) recognized in other non-operating income of CIVs	$ (166)	$ (3,264)
Debt Instrument Basis, Spread on Variable Rate Basis Points, Low End of Range	0.25%
Debt Instrument Basis, Spread on Variable Rate Basis Points, High End of Range	4.00%
Derivative Liabilities	2,573		2,930
Gain on Derivative Assets and Liabilities Recorded in Other Non-Operating Income of Consolidated Investment Vehicles	357	252
Loss on Derivative Assets and Liabilities Recorded in Other Non-Operating Income of Consolidated Investment Vehicles	$ (315)	$ (299)