BORROWINGS (Details 2) - USD ($)		3 Months Ended	12 Months Ended
		Mar. 31, 2016	Dec. 31, 2015
Repurchase Agreement Counterparty [Line Items]
Repurchase Agreement Counterparties, Amount Outstanding		$ 469,626,356	$ 568,432,457	[1]
Repurchase Agreement Counterparties, Percent of total amount outstanding		100.00%	100.00%
Repurchase Agreement Counterparties, Weighted average days to maturity		21 days	26 days
Repurchase Agreement Counterparties, Market Value of collateral held		$ 593,964,442	$ 697,384,372
Merrill Lynch [Member]
Repurchase Agreement Counterparty [Line Items]
Repurchase Agreement Counterparties, Amount Outstanding		$ 58,772,000	$ 99,770,000	[1]
Repurchase Agreement Counterparties, Percent of total amount outstanding		12.51%	17.55%
Repurchase Agreement Counterparties, Weighted average days to maturity		33 days	30 days
Repurchase Agreement Counterparties, Market Value of collateral held		$ 112,001,570	$ 154,005,234
Wells Fargo Securities [Member]
Repurchase Agreement Counterparty [Line Items]
Repurchase Agreement Counterparties, Amount Outstanding		$ 29,575,000	$ 32,192,000	[1]
Repurchase Agreement Counterparties, Percent of total amount outstanding		6.30%	5.66%
Repurchase Agreement Counterparties, Weighted average days to maturity		10 days	10 days
Repurchase Agreement Counterparties, Market Value of collateral held		$ 52,487,778	$ 53,711,547
Other North America [Member]
Repurchase Agreement Counterparty [Line Items]
Repurchase Agreement Counterparties, Amount Outstanding		$ 244,249,000	$ 291,806,000	[1]
Repurchase Agreement Counterparties, Percent of total amount outstanding		52.01%	51.34%
Repurchase Agreement Counterparties, Weighted average days to maturity		15 days	25 days
Repurchase Agreement Counterparties, Market Value of collateral held		$ 261,289,732	$ 315,040,818
Asia [Member]
Repurchase Agreement Counterparty [Line Items]
Repurchase Agreement Counterparties, Amount Outstanding	[1]	$ 84,887,000	$ 88,565,000
Repurchase Agreement Counterparties, Percent of total amount outstanding	[1]	18.08%	15.58%
Repurchase Agreement Counterparties, Weighted average days to maturity	[1]	17 days	16 days
Repurchase Agreement Counterparties, Market Value of collateral held	[1]	$ 96,092,316	$ 97,970,226
Europe [Member]
Repurchase Agreement Counterparty [Line Items]
Repurchase Agreement Counterparties, Amount Outstanding	[1]	$ 52,143,356	$ 56,099,457
Repurchase Agreement Counterparties, Percent of total amount outstanding	[1]	11.10%	9.87%
Repurchase Agreement Counterparties, Weighted average days to maturity	[1]	44 days	46 days
Repurchase Agreement Counterparties, Market Value of collateral held	[1]	$ 72,093,046	$ 76,656,547

[1] Counterparties domiciled in Europe and Asia, or their U.S. subsidiaries.