CONSOLIDATED STATEMENTS OF CHANGES IN NET ASSETS (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Operations:
Net investment income	$ 4,421	$ 3,271
Net realized gain on investments	10,079	45,748
Net increase (decrease) in unrealized appreciation of investments	165	(20,545)
Increase in net assets from operations	14,665	28,474
Distributions from:
Undistributed net investment income	(3,003)	(2,993)
Net realized gains deemed distributed to shareholders	(3,216)	(45,748)
Capital share transactions:
Allocated increase in share value for deemed distribution	3,216	45,748
Exercise of employee stock options	98	745
Stock option expense	757	712
Increase in net assets	12,517	26,938
Net assets, beginning of period	539,233	486,925
Net assets, end of period	$ 551,750	$ 513,863