Note 4 - Shareholders' Equity and Preferred Stock (Details Textual) - USD ($)					12 Months Ended
	Jul. 08, 2021	Jun. 08, 2021	Mar. 30, 2020	Dec. 27, 2019	Dec. 31, 2021	Dec. 31, 2020	Nov. 14, 2019	Nov. 26, 2014
Stock Repurchased and Retired During Period, Shares (in shares)					434,381	245,534
Stock Repurchased and Retired During Period, Value					$ 25,219,000	$ 3,353,000
Own-share Lending Arrangement, Shares, Outstanding (in shares)						1,459,233
Class B Preferred Units [Member]
Preferred Units, Issued (in shares)							50,500,000
Preferred Unit Purchase Price (in dollars per share)							$ 1.00
Preferred Units Issued, Percentage of Preferred Return							16.00%
Preferred Units Issued, Maximum Percentage Points of Preferred Return in Form of Issuance of Additional Units or Cash							6.00%
Additional Preferred Units Issued (in shares)			50,000,000.0
Series A Preferred Stock [Member]
Preferred stock, shares issued (in shares)				400,000	400,000	400,000
Preferred stock, liquidation preference				$ 40,000,000.0	$ 40,000,000	$ 40,000,000
Preferred Stock, Dividend Rate, Percentage				6.00%
Temporary Equity, Redemption Price Per Share (in dollars per share)				$ 100
Temporary Equity, Conversion Price Per Share (in dollars per share)				$ 10
Series B Preferred Stock [Member]
Stock Issued During Period, Shares, New Issues (in shares)	388,533
Preferred Stock, No Par Value (in dollars per share)					$ 0	$ 0
Proceeds from Issuance of Preferred Stock and Preference Stock	$ 9,700,000
Preferred Stock, Redemption Price Per Share (in dollars per share)	$ 25.00
Series B Preferred Stock [Member] | Public Offering [Member]
Preferred Stock, Dividend Rate, Percentage		7.625%
Stock Issued During Period, Shares, New Issues (in shares)		2,800,000
Preferred Stock, No Par Value (in dollars per share)		$ 0
Preferred Stock, Liquidation Preference Per Share (in dollars per share)		25.00
Shares Issued, Price Per Share (in dollars per share)		$ 25.00
Proceeds from Issuance of Preferred Stock and Preference Stock		$ 70,000,000.0
Dove Ventures, LLC [Member] | Senior Secured Term Loan Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity								$ 40,000,000.0
Extinguishment of Debt, Amount				$ 40,000,000.0