CONSOLIDATED STATEMENTS OF ASSETS AND LIABILITIES (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2011	Mar. 31, 2011
Investments at market or fair value
Companies more than 25% owned, Cost	$ 14,870	$ 25,521
Companies 5% to 25% owned, Cost	14,003	14,049
Companies less than 5% owned, Cost	59,820	58,784
Total investments, Cost	$ 88,693	$ 98,354
Net Assets
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, authorized (in shares)	5,000,000	5,000,000
Common stock, issued (in shares)	4,339,416	4,337,916
Treasury stock (in shares)	584,878	584,878
Net asset value per share (in shares)	3,754,538	3,753,038