Note 3 - Equity (Details Textual) - USD ($)	3 Months Ended				14 Months Ended	19 Months Ended	47 Months Ended
	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Aug. 31, 2021	May 18, 2021	Mar. 31, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	May 09, 2019
Preferred Stock, Par or Stated Value Per Share	$ 0.01					$ 0.01	$ 0.01	$ 0.01
Stock Repurchase Program, Authorized Amount	$ 21,000,000			$ 4,000,000	$ 8,000,000.0	$ 21,000,000	$ 21,000,000			$ 4,000,000.0
Stock Repurchase Program, Increase in Authorized Amount				$ 12,000,000.0	$ 4,000,000	9,000,000.0
Stock Repurchased During Period, Shares	74,150	88,741	20,859				1,897,819
Shares Acquired, Average Cost Per Share	$ 5.79	$ 5.05	$ 4.97				$ 5.88
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 9,835,910	$ 10,265,181	$ 10,713,447			$ 9,835,910	$ 9,835,910
Blank Check [Member]
Preferred Stock, Shares Authorized	30,000,000					30,000,000	30,000,000
Preferred Stock, Par or Stated Value Per Share	$ 0.01					$ 0.01	$ 0.01
Series B Preferred Stock [Member]
Preferred Stock, Shares Authorized	700,000					700,000	700,000	700,000
Preferred Stock, Shares, Number	700,000
Preferred Stock, Shares Outstanding, Ending Balance (in shares)	625,375					625,375	625,375	625,375
Preferred Stock, Shares Issued	625,375					625,375	625,375	625,375	625,375
Series B-1 Preferred Stock [Member]
Preferred Stock, Shares Authorized	550,000					550,000	550,000	550,000
Preferred Stock, Shares, Number	550,000
Preferred Stock, Cash, Dividend Rate, Percentage	7.00%
Preferred Stock, Series B Preferred Shares, Dividend Rate, Percentage	9.00%
Preferred Stock, Redemption Price Per Share	$ 10.70					$ 10.70	$ 10.70
Preferred Stock, Shares Outstanding, Ending Balance (in shares)	212,402					212,402	212,402	212,402
Preferred Stock, Shares Issued	212,402					212,402	212,402	212,402	212,402
Share-Based Payment Arrangement, Nonemployee [Member]
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 5,000,000.0					$ 5,000,000.0	$ 5,000,000.0
Restricted Stock Units (RSUs) [Member] | Share-Based Payment Arrangement, Nonemployee [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding, Number	940,451					940,451	940,451	906,155
Restricted Stock Units (RSUs) [Member] | Vested and Unissued [Member] | Share-Based Payment Arrangement, Nonemployee [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding, Number	25,054					25,054	25,054