Related Party Revenue (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Related party transactions:
Interest income revenue	$ 3,821	$ 6,169
Management fees revenue	4,860	4,735
Revenue from related parties	8,681	10,904
SAC Holdings
Related party transactions:
Interest income revenue	2,476	4,816
Management fees revenue	3,829	3,729
Private Mini
Related party transactions:
Interest income revenue	1,345	1,353
Management fees revenue	567	552
Mercury
Related party transactions:
Management fees revenue	$ 464	$ 454