Note 1 - Organization and Description of Business (Details Textual) - USD ($) $ in Thousands				1 Months Ended		12 Months Ended
	Sep. 26, 2019	Mar. 19, 2019		May 31, 2019	Mar. 31, 2019	Dec. 31, 2019	Sep. 27, 2019	Jan. 17, 2019	Dec. 31, 2018
Deconsolidation, Gain (Loss), Amount		$ 3,192
Proceeds from Divestiture of Interest in Consolidated Subsidiaries		7,942
Investments, Fair Value Disclosure, Total		74,989	[1]			$ 14,206			$ 9,913
Unamortized Debt Issuance Expense						3,416			$ 2,428
The 2019 Senior Notes [Member]
Proceeds From Bonds	$ 36,000
Debt Instrument, Interest Rate, Stated Percentage	6.875%
Senior Notes 2013 [Member]
Debt Instrument, Interest Rate, Stated Percentage							8.00%
Unamortized Debt Issuance Expense						500
Interest Expense, Debt, Total						$ 200
CLO III [Member]
Net Assets, Ending Balance		24,500
CLO IV [Member]
Net Assets, Ending Balance		30,200
CLO V [Member]
Net Assets, Ending Balance		25,800
CLO VI [Member]
Net Assets, Ending Balance		11,600
JMPCA [Member]
Net Assets, Ending Balance		500
Senior Subordinated Notes of CLO IV and CLO V [Member]
Debt Securities, Trading, Realized Gain (Loss), Total				$ (100)
CLO III [Member]
Investments, Fair Value Disclosure, Total		13,300
CLO IV [Member]
Investments, Fair Value Disclosure, Total		27,800
CLO V [Member]
Investments, Fair Value Disclosure, Total		26,500
CLO VI [Member]
Investments, Fair Value Disclosure, Total		3,800
JMPCA [Member]
Investments, Fair Value Disclosure, Total		$ 3,600
Medalist Partners LP [Member]
Percentage of Outstanding Preference Shares Sold		66.00%
Proceeds from Sale of Preference shares		$ 7,600
Gain (Loss) on Sale of Preference Shares		0
CLO III [Member]
Ownership Percentage of Junior Subordinated Notes								47.00%
Deconsolidation, Gain (Loss), Amount					$ 1,600
JMPCA [Member]
Deconsolidation, Gain (Loss), Amount		$ 3,400
Ownership Percentage		45.00%
Proceeds from Divestiture of Interest in Consolidated Subsidiaries		$ 300
JMPCA [Member] | Medalist Partners LP [Member]
Ownership Interest, Sold		50.10%
JMPCA [Member] | Management Employees of JMPCA [Member]
Ownership Interest, Sold		4.90%
CLO's [Member]
Ownership Percentage		100.00%
CLO IV [Member]
Ownership Percentage of Junior Subordinated Notes						100.00%
Ownership Percentage of Senior Subordinated Notes		100.00%
CLO VI [Member]
Ownership Percentage of Junior Subordinated Notes						33.00%
CLO V [Member]
Ownership Percentage of Senior Subordinated Notes		25.00%
CLO IV, CLO V, and CLO VI [Member]
Deconsolidation, Gain (Loss), Amount					$ (1,800)

[1] The fair value of the Company's retained interest in CLO III, CLO IV, CLO V, CLO VI, and JMPCA as of the deconsolidation date was $13.3 million, $27.8 million, $26.5 million, $3.8 million, and $3.6 million, respectively