INVESTMENTS (Details) (USD $)	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
INVESTMENTS [Abstract]
Portfolio investments categorized as Level 3 (in hundredths)	70.80%	56.90%
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	$ 406,500,000	$ 317,800,000
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	574,200,000	558,500,000
Summary of changes in fair value of investments [Roll Forward]
Fair value at beginning of period	317,800,000	462,500,000
Net Unrealized Appreciation (Depreciation)	90,500,000	79,700,000
New Investments	4,500,000	14,200,000
Divestures	(9,800,000)	(7,100,000)
Net Changes from Unrealized to Realized	3,500,000	(4,400,000)
Conversion of Security from Debt to Equity	0	0
Transfers out of Level 3	0	227,100,000
Fair value at end of period	406,500,000	317,800,000
Unrealized gains (losses) included in earnings that related to asset still held at report date	120,777,969	96,949,860
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	167,700,000	240,700,000
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	0	0
Significant Observable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	406,500,000	317,800,000
Debt [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	6,600,000	11,200,000
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	6,600,000	11,200,000
Summary of changes in fair value of investments [Roll Forward]
Fair value at beginning of period	11,200,000	12,700,000
Net Unrealized Appreciation (Depreciation)	(5,400,000)	(4,600,000)
New Investments	4,000,000	6,600,000
Divestures	0	(1,000,000)
Net Changes from Unrealized to Realized	0	(2,500,000)
Conversion of Security from Debt to Equity	(3,200,000)	0
Transfers out of Level 3	0	0
Fair value at end of period	6,600,000	11,200,000
Debt [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	0	0
Debt [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	0	0
Debt [Member] | Significant Observable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	6,600,000	11,200,000
Debt [Member] | Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	3,100,000	8,000,000
Weighted Average Discount Rate (in hundredths)	10.77%	14.74%
Debt [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount Rate (in hundredths)	10.02%	10.31%
Debt [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount Rate (in hundredths)	12.00%	16.22%
Debt [Member] | Recent Transaction Price [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	3,500,000	3,200,000
Partnership Interest [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	12,200,000	11,000,000
Summary of changes in fair value of investments [Roll Forward]
Fair value at beginning of period	11,000,000	9,500,000
Net Unrealized Appreciation (Depreciation)	1,500,000	200,000
New Investments	500,000	1,300,000
Divestures	0	0
Net Changes from Unrealized to Realized	(800,000)	0
Conversion of Security from Debt to Equity	0	0
Transfers out of Level 3	0	0
Fair value at end of period	12,200,000	11,000,000
Partnership Interest [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	0	0
Partnership Interest [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	0	0
Partnership Interest [Member] | Significant Observable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	12,200,000	11,000,000
Partnership Interest [Member] | Net Asset Value [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	12,200,000	11,000,000
Preferred Equity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	44,600,000	33,900,000
Summary of changes in fair value of investments [Roll Forward]
Fair value at beginning of period	33,900,000	45,800,000
Net Unrealized Appreciation (Depreciation)	12,300,000	(2,900,000)
New Investments	0	6,300,000
Divestures	(9,800,000)	(6,100,000)
Net Changes from Unrealized to Realized	5,000,000	(9,200,000)
Conversion of Security from Debt to Equity	3,200,000	0
Transfers out of Level 3	0	0
Fair value at end of period	44,600,000	33,900,000
Preferred Equity [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	0	0
Preferred Equity [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	0	0
Preferred Equity [Member] | Significant Observable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	44,600,000	33,900,000
Common Equity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	510,800,000	502,400,000
Summary of changes in fair value of investments [Roll Forward]
Fair value at beginning of period	261,700,000	394,500,000
Net Unrealized Appreciation (Depreciation)	82,100,000	87,000,000
New Investments	0	0
Divestures	0	0
Net Changes from Unrealized to Realized	(700,000)	7,300,000
Conversion of Security from Debt to Equity	0	0
Transfers out of Level 3	0	227,100,000
Fair value at end of period	343,100,000	261,700,000
Common Equity [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	167,700,000	240,700,000
Common Equity [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	0	0
Common Equity [Member] | Significant Observable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	343,100,000	261,700,000
Preferred & Common Equity [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	387,700,000	295,600,000
Preferred & Common Equity [Member] | Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	342,200,000	270,200,000
Weighted Average Multiple	6.45	5.71
Preferred & Common Equity [Member] | Market Approach [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Multiple	3.25	3.25
Preferred & Common Equity [Member] | Market Approach [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Multiple	7.00	6.50
Preferred & Common Equity [Member] | Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	11,100,000	11,700,000
Weighted Average Multiple	0.97	1.48
Preferred & Common Equity [Member] | Market Approach [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Multiple	0.25	1.10
Preferred & Common Equity [Member] | Market Approach [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Multiple	1.82	1.97
Preferred & Common Equity [Member] | Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	7,900,000	5,500,000
Preferred & Common Equity [Member] | Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	700,000	800,000
Discount Rate (in hundredths)	1.75%	3.56%
Weighted Average Discount Rate (in hundredths)	1.75%	3.56%
Preferred & Common Equity [Member] | Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	3,000,000	2,300,000
Multiple	1.22	1.00
Weighted Average Multiple	1.22	1.00
Preferred & Common Equity [Member] | Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	22,600,000	5,000,000
Preferred & Common Equity [Member] | Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	$ 200,000	$ 100,000