INCOME TAXES (Details) (USD $)	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011
INCOME TAXES [Abstract]
Annual distribution minimum (in hundredths)	90.00%
Ordinary dividends declared and paid	$ 3,025,032		$ 3,003,030
Federal excise tax (in hundredths)	4.00%
Minimum distribution to avoid excise tax (in hundredths)	98.00%
Investment company ordinary taxable income, Maximum (in hundredths)		100.00%		100.00%
Federal tax rate (in hundredths)	35.00%
Distributed net capital gains (in dollars per share)	$ 20.34	$ 17.59
Net long term unrealized capital gains, tax basis		3,214,547		3,568,376
Net long-term capital gains, book basis		2,319,012		4,465,088
Long term capital gains federal taxes		1,125,092		1,248,932
Schedule of Cost-method Investments [Line Items]
Net realized gain on investments	89,557,814		11,826,876		63,462,583
Income tax expense	2,497,000		2,662,000		1,930,000
Period expected to maintain regulated investment company status	1 year
Net Realized Gains (Losses) on Investments [Member]
Schedule of Cost-method Investments [Line Items]
Net realized gain on investments		69,144,794		4,465,088
Capital gain distribution		(66,825,782)		0
Income tax expense		1,125,092		1,248,932
Net realized gains on investments		1,193,920		3,216,156
Net realized gains on investment (for tax purposes)		3,214,547		3,568,376
Control Investment [Member] | Net Realized Gains (Losses) on Investments [Member]
Schedule of Cost-method Investments [Line Items]
Net realized gain on investments		0		0
Affiliated Investments [Member] | Net Realized Gains (Losses) on Investments [Member]
Schedule of Cost-method Investments [Line Items]
Net realized gain on investments		66,037,485		0
Non-Control/Non-Affiliated Investments [Member] | Net Realized Gains (Losses) on Investments [Member]
Schedule of Cost-method Investments [Line Items]
Net realized gain on investments		$ 3,107,309		$ 4,465,088