Note 4 - Insurance SPAC Investments and Other Significant Events (Details Textual)										1 Months Ended								6 Months Ended		11 Months Ended	12 Months Ended
	Mar. 31, 2021 USD ($)	Dec. 22, 2020 USD ($) $ / shares shares	Dec. 21, 2020 shares	Nov. 24, 2020 $ / shares shares	Oct. 15, 2020 USD ($) $ / shares shares	Sep. 30, 2020 USD ($)	Feb. 03, 2020 USD ($)	Dec. 30, 2019 USD ($) $ / shares shares	Mar. 22, 2019 shares	Dec. 31, 2020 USD ($) $ / shares shares	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) $ / shares shares	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Nov. 24, 2020 $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 22, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) shares	Sep. 25, 2020 USD ($)	Jan. 31, 2020 USD ($)	Dec. 29, 2019	Dec. 31, 2017 USD ($) shares	Sep. 29, 2017 USD ($)	Sep. 01, 2017 $ / shares	Aug. 31, 2017 $ / shares	Oct. 03, 2016 USD ($)
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares										$ 0.01				$ 0.01							$ 0.01		$ 0.01							$ 0.01	$ 0.001
Other Investments, Total										$ 21,878,000				$ 14,315,000							$ 21,878,000		$ 14,315,000
Other Investment Sold, Not yet Purchased										7,415,000											7,415,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance										101,437,000				48,756,000							101,437,000		48,756,000	$ 42,438,000				$ 48,156,000
Equity Method Investments										13,482,000				3,799,000							13,482,000		3,799,000
Stockholders' Equity Attributable to Noncontrolling Interest, Ending Balance										$ 57,528,000				$ 15,437,000							$ 57,528,000		$ 15,437,000	$ 6,664,000				$ 8,284,000
Common Stock, Shares, Issued, Total (in shares) | shares										1,325,529				1,193,624							1,325,529		1,193,624
Common Unit, Outstanding (in shares) | shares										38,418,255				38,952,715							38,418,255		38,952,715	16,431,254				16,934,944
Goodwill, Impairment Loss													$ 7,883,000								$ 7,883,000
Proceeds from Issuance of Long-term Debt, Total																					2,166,000
Long-term Debt, Total										47,100,000				48,861,000							47,100,000		48,861,000
Redeemable Financial Instruments										11,957,000				16,983,000							11,957,000		16,983,000
Alternative Investment										2,548				2,891,000							2,548		2,891,000
ViaNova [Member]
Other Investment Not Readily Marketable, Quoted Value										2,300,000											2,300,000
Other Investment Not Readily Marketable, Fair Value										2,243,000											2,243,000
JKD Capital Partners I, LTD [Member]
Redeemable Financial Instruments										$ 7,957,000				7,957,000							$ 7,957,000		7,957,000
JKD Capital Partners I, LTD [Member] | Investment Agreement [Member]
Redeemable Financial Instruments																																$ 12,000,000
CBF [Member] | Investment Agreement [Member]
Redeemable Financial Instruments					$ 4,000,000																				$ 6,500,000				$ 8,000,000
Payments for Redeemable Financial Instruments					$ 2,500,000
Investment Agreement, Percentage of Investment Return on Investment Amount for Revenues Greater than Zero					20.00%					20.00%											20.00%
Investment Agreement, Percentage of Investment Return on Business Revenue for Revenues Greater than Zero					9.40%					15.20%											15.20%
Investment Agreement, Percentage of Investment Return on Investment Amount for Revenues with Zero or Less than Zero					3.75%					3.75%											3.75%
CBF [Member] | Investment Agreement [Member] | Forecast [Member]
Payments for Redeemable Financial Instruments	$ 4,000
DGC Trust [Member]
Redeemable Financial Instruments						$ 2,000,000					$ 2,000,000							$ 2,000,000
DGC Trust [Member] | Investment Agreement [Member]
Redeemable Financial Instruments																									$ 2,000,000				$ 2,000,000
Payments for Redeemable Financial Instruments						$ 2,000,000
Daniel G. Cohen And DGC Trust [Member] | IMXI [Member]
Alternative Investment								$ 7,779,000
Paycheck Protection Program CARES Act [Member]
Proceeds from Issuance of Long-term Debt, Total																		$ 2,166,000
Non-convertible Senior Notes 12.00% (2020 Senior Notes) [Member] | Non-convertible Senior Notes [Member]
Debt Instrument, Face Amount																										$ 4,500,000
Debt Instrument, Interest Rate, Stated Percentage							12.00%
Non-convertible Senior Notes 12.00% (2020 Senior Notes) [Member] | JKD Capital Partners I, LTD [Member] | Non-convertible Senior Notes [Member]
Debt Instrument, Face Amount																										$ 2,250,000
Debt Instrument, Interest Rate, Stated Percentage																										12.00%
Non-convertible Senior Notes 12.00% (2020 Senior Notes) [Member] | JKD Capital Partners I LTD and RN Capital Solutions LLC [Member] | Non-convertible Senior Notes [Member]
Debt Instrument, Face Amount																										$ 4,500,000
The 2019 Senior Notes [Member]
Repayments of Debt							$ 4,386,000
Long-term Debt, Total							$ 2,400,000
COVID-19 Pandemic [Member] | JVB Holdings [Member]
Goodwill, Impairment Loss																			$ 7,883,000		$ 7,883,000
SPAC II Sponsor Entities [Member]
Equity Method Investments										$ 4,064,000											4,064,000
Stockholders' Equity Attributable to Noncontrolling Interest, Ending Balance										4,295,000											4,295,000
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity, Total										(231,000)											(231,000)
Insurance SPAC III Sponsor Entities [Member]
Investments, Total										325,000											325,000
Equity Method Investments										5,741,000											5,741,000
Stockholders' Equity Attributable to Noncontrolling Interest, Ending Balance										5,416,000											5,416,000
CK Capital Partners B.V. [Member]
Equity Method Investments										$ 296,000				$ 18,000							$ 296,000		$ 18,000
Equity Method Investment, Ownership Percentage														45.00%									45.00%
Equity Method Investment, Quoted Market Value														$ 18,000									$ 18,000
CK Capital Partners B.V. [Member] | Daniel G. Cohen [Member]
Equity Method Investment, Quoted Market Value														$ 17,000									$ 17,000
SPA [Member]
Economic Interest, Percentage																					28.75%
COHN, LLC [Member]
Economic Interest, Percentage																					28.75%
Voting Interest, Percentage																					51.00%
Noncontrolling Interest, Ownership Percentage by Parent										72.96%				71.25%							72.96%		71.25%	32.40%			32.22%
SFT Class A Common Stock [Member]
Investment Owned, Balance, Shares (in shares) | shares					350,000
AOI [Member]
Equity Method Investment, Ownership Percentage														10.00%									10.00%
Equity Method Investment, Quoted Market Value														$ 1,000									$ 1,000
Equity Method Investment, Aggregate Cost														$ 558,000									$ 558,000
Sponsor Entities [Member] | Private Placement [Member] | Insurance SPAC [Member]
Number of Placement Units Purchased (in shares) | shares									375,000
Sponsor Entities [Member] | SFT Class A Common Stock [Member]
Investment Owned, Balance, Shares (in shares) | shares					375,000
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares					$ 0.0001
Sponsor Entities [Member] | SFT Warrants [Member]
Investment Owned, Balance, Shares (in shares) | shares					187,500
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares					$ 11.50
Sponsor Entities [Member] | Sponsor Shares [Member]
Investment Owned, Balance, Shares (in shares) | shares					4,497,525
Operating LLC [Member] | SFT [Member]
Other Investments, Total										$ 36,395,000											$ 36,395,000
Other Investment Sold, Not yet Purchased										1,337,000											1,337,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance										$ 16,686,000											$ 16,686,000
Operating LLC [Member] | INSU Pipe LLC [Member]
Distribution Made to Parent's Wholly Owned Subsidiary, Securities to be Distributed (in shares) | shares																					350,000
Ownership Percentage										100.00%											100.00%
Operating LLC [Member] | Private Placement [Member] | Insurance SPAC [Member]
Number of Placement Units Purchased (in shares) | shares									122,665
Operating LLC [Member] | Sponsor Shares [Member]
Investment Owned, Balance, Shares (in shares) | shares					2,019,721
Operating LLC [Member] | Shift [Member]
Investments, Total										$ 18,372,000											$ 18,372,000
Company's Subsidiary [Member] | SFT Class A Common Stock [Member]
Investment Owned, Balance, Shares (in shares) | shares										600,000											600,000
Investment Owned, Price Per Share (in dollars per share) | $ / shares										$ 10											$ 10
Distribution Made to Parent's Wholly Owned Subsidiary, Securities to be Distributed (in shares) | shares																					250,000
SPAC II [Member] | Private Placement [Member]
Units Issued During Period, Units, New Issues (in shares) | shares				452,500
SPAC II [Member] | Founder Shares [Member]
Units Issued During Period, Units, New Issues (in shares) | shares				6,669,667
SPAC II [Member] | IPO [Member]
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares				$ 11.50																$ 11.50
Units Issued During Period, Shares Per Unit (in shares) | shares																				1
Units Issued During Period, Warrants Per Unit (in shares) | shares																				0.33
SPAC II [Member] | Sponsor Shares [Member] | Share-based Payment Arrangement, Tranche One [Member]
Number of Common Stock, Vested (in shares) | shares				765,833																765,833
Number of Common Stock, Available to Vest (in shares) | shares				1,244,479																1,244,479
SPAC II [Member] | Sponsor Shares [Member] | Share-based Payment Arrangement, Tranche Two [Member]
Number of Common Stock, Available to Vest (in shares) | shares				1,244,479																1,244,479
SPAC II [Member] | Founder Shares [Member]
Number of Common Stock, Vested (in shares) | shares				1,569,333																1,569,333
SPAC II [Member] | Founder Shares [Member] | Share-based Payment Arrangement, Tranche One [Member]
Number of Common Stock, Available to Vest (in shares) | shares				2,550,167																2,550,167
SPAC II [Member] | Founder Shares [Member] | Share-based Payment Arrangement, Tranche Two [Member]
Number of Common Stock, Available to Vest (in shares) | shares				2,550,167																2,550,167
MetroMile [Member] | Share-based Payment Arrangement, Tranche One [Member] | Minimum [Member]
Trigger Share Price For Share Vesting (in dollars per share) | $ / shares				$ 15																$ 15
MetroMile [Member] | Share-based Payment Arrangement, Tranche Two [Member] | Minimum [Member]
Trigger Share Price For Share Vesting (in dollars per share) | $ / shares				17																17
MetroMile [Member] | Sponsor Shares [Member] | Share-based Payment Arrangement, Tranche One [Member]
Trigger Share Price For Share Vesting (in dollars per share) | $ / shares				$ 15																$ 15
Insurance SPAC III Sponsor Entities [Member]
Sale of Stock, Number of Shares Issued in Transaction (in shares) | shares		25,000,000
Option Period On Additional Units To Be Purchased (Day)		45 days
Sale of Stock, Number of Shares Issuable, Option (in shares) | shares		3,270,000																				3,270,000
Common Stock, Shares, Issued, Total (in shares) | shares		34,100,000																				34,100,000
Common Unit, Outstanding (in shares) | shares		34,100,000																				34,100,000
Payments of Stock Issuance Costs																					$ 71,000
Commitments, Operating and Acquisition Expenses										$ 810,000											$ 810,000
Insurance SPAC III Sponsor Entities [Member] | Insurance SPAC Warrant III [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares		$ 11.50																				$ 11.50
Units Issued During Period, Warrants Per Unit (in shares) | shares		0.33
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | shares		1																				1
Shares Issued, Price Per Share (in dollars per share) | $ / shares		$ 10																				$ 10
Insurance SPAC III Sponsor Entities [Member] | Common Class A [Member]
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares		$ 0.0001																				0.0001
Units Issued During Period, Shares Per Unit (in shares) | shares		1
Insurance SPAC III Sponsor Entities [Member] | Private Placement [Member]
Sale of Stock, Number of Shares Issued in Transaction (in shares) | shares		575,000
Insurance SPAC III Sponsor Entities [Member] | IPO [Member]
Shares Issued, Price Per Share (in dollars per share) | $ / shares		$ 10																				$ 10
Sale of Stock, Consideration Received on Transaction		$ 5,750,000
Proceeds From Issuance of Units, Trust Account		250,000,000																				$ 250,000,000
Payments of Equity Issuance Costs, Trust Account		$ 10,600,000
Percentage of Public Shares Redeemed		100.00%																				100.00%
Insurance SPAC III Sponsor Entities [Member] | Over-Allotment Option [Member]
Sale of Stock, Number of Shares Issued in Transaction (in shares) | shares		3,200,000	3,200,000
Insurance SPAC III Sponsor Entities [Member] | Founder Shares [Member]
Investment Owned, Balance, Shares (in shares) | shares		8,525,000																				8,525,000
Founder Shares, Percent of Shares to Become Transferable or Salable Upon Consummation of Business Combination		25.00%																				25.00%
Closing Share Price for Founder Shares to Become Transferable or Salable, Tranche One (in dollars per share) | $ / shares		$ 12																				$ 12
Closing Share Price for Founder Shares to Become Transferable or Salable, Tranche Two (in dollars per share) | $ / shares		13.50																				13.50
Closing Share Price for Founder Shares to Become Transferable or Salable, Tranche Three (in dollars per share) | $ / shares		$ 17																				$ 17
Equity Method Investment, Shares Purchased (in shares) | shares																						4,467,500
Insurance SPAC [Member] | Insurance SPAC Warrant III [Member]
Proceeds From Issuance of Units		$ 250,000,000
Schedule Of Other Investments Equity Security [Member]
Sale of Stock, Number of Shares Issued in Transaction (in shares) | shares								662,361
Sale of Stock, Number of Unrestricted Shares Issued in Transaction (in shares) | shares								134,317
Sale of Stock, Number of Restricted Shares Issued in Transaction (in shares) | shares								528,044
Schedule Of Other Investments Equity Security [Member] | Closing Price Tranche 1 [Member]
Sale of Stock, Number of Restricted Shares Becoming Tradeable, Issued in Transaction (in shares) | shares								264,021
Sale of Stock, Price Per Share (in dollars per share) | $ / shares								$ 15
Period Out Of Consecutive 30 Trading Days For Transferable Or Salable Price Tranches To Hit (Year)								20 years
Schedule Of Other Investments Equity Security [Member] | Tranche Two [Member]
Sale of Stock, Number of Restricted Shares Becoming Tradeable, Issued in Transaction (in shares) | shares								264,023
Sale of Stock, Price Per Share (in dollars per share) | $ / shares								$ 17
Period Out Of Consecutive 30 Trading Days For Transferable Or Salable Price Tranches To Hit (Year)								20 years
COHN, LLC [Member]
Share Price (in dollars per share) | $ / shares								$ 11.89
Membership Units Received, Net Of Surrenders (in shares) | shares								22,429,541
Common Share Exchange Ratio								10
Convertible Amount Of Shares (in shares) | shares								2,242,954
COHN, LLC [Member] | Daniel G. Cohen And DGC Trust [Member] | IMXI [Member]
Membership Units Received, Net Of Surrenders (in shares) | shares								22,429,541
Common Share Exchange Ratio								10
Convertible Amount Of Shares (in shares) | shares								2,242,954
SPA [Member] | SPA [Member]
Equity Method Investment, Ownership Percentage										67.80%											67.80%