Note 8 - Debt - Schedule of Outstanding Principal Balances Related to SFR Loans (Details) - Senior Loan [Member] $ in Thousands	Sep. 30, 2021 USD ($)
Single Family Rental [Member]
Secured financing agreements, net	$ 745,513
Interest Rate	2.42%
Single Family Rental [Member] \| Debt Instrument One [Member]
Secured financing agreements, net	$ 465,691
Interest Rate	2.24%
Single Family Rental [Member] \| Debt Instrument Two [Member]
Secured financing agreements, net	$ 55,988
Interest Rate	2.70%
Single Family Rental [Member] \| Debt Instrument Three [Member]
Secured financing agreements, net	$ 46,094
Interest Rate	2.14%
Single Family Rental [Member] \| Debt Instrument Four [Member]
Secured financing agreements, net	$ 35,477
Interest Rate	2.70%
Single Family Rental [Member] \| Debt Instrument Five [Member]
Secured financing agreements, net	$ 15,853
Interest Rate	2.91%
Single Family Rental [Member] \| Debt Instrument Six [Member]
Secured financing agreements, net	$ 11,090
Interest Rate	3.02%
Single Family Rental [Member] \| Debt Instrument Seven [Member]
Secured financing agreements, net	$ 9,487
Interest Rate	2.79%
Single Family Rental [Member] \| Debt Instrument Eight [Member]
Secured financing agreements, net	$ 9,285
Interest Rate	2.45%
Single Family Rental [Member] \| Debt Instrument Nine [Member]
Secured financing agreements, net	$ 9,091
Interest Rate	3.51%
Single Family Rental [Member] \| Debt Instrument Ten [Member]
Secured financing agreements, net	$ 8,887
Interest Rate	3.30%
Single Family Rental [Member] \| Debt Instrument Eleven [Member]
Secured financing agreements, net	$ 8,152
Interest Rate	3.14%
Single Family Rental [Member] \| Debt Instrument Twelve [Member]
Secured financing agreements, net	$ 7,561
Interest Rate	3.02%
Single Family Rental [Member] \| Debt Instrument Thirteen [Member]
Secured financing agreements, net	$ 7,194
Interest Rate	2.80%
Single Family Rental [Member] \| Debt Instrument Fourteen [Member]
Secured financing agreements, net	$ 6,914
Interest Rate	2.98%
Single Family Rental [Member] \| Debt Instrument Fifteen [Member]
Secured financing agreements, net	$ 6,794
Interest Rate	2.69%
Single Family Rental [Member] \| Debt Instrument Sixteen [Member]
Secured financing agreements, net	$ 6,063
Interest Rate	2.99%
Single Family Rental [Member] \| Debt Instrument Seventeen [Member]
Secured financing agreements, net	$ 5,741
Interest Rate	2.68%
Single Family Rental [Member] \| Debt Instrument Eighteen [Member]
Secured financing agreements, net	$ 5,740
Interest Rate	2.40%
Single Family Rental [Member] \| Debt Instrument Nineteen [Member]
Secured financing agreements, net	$ 5,346
Interest Rate	3.14%
Single Family Rental [Member] \| Debt Instrument Twenty [Member]
Secured financing agreements, net	$ 5,120
Interest Rate	2.64%
Single Family Rental [Member] \| Debt Instrument Twenty One [Member]
Secured financing agreements, net	$ 4,870
Interest Rate	2.48%
Single Family Rental [Member] \| Debt Instrument Twenty Two [Member]
Secured financing agreements, net	$ 4,829
Interest Rate	2.97%
Single Family Rental [Member] \| Debt Instrument Twenty Three [Member]
Secured financing agreements, net	$ 4,246
Interest Rate	3.06%
Single Family Rental [Member] \| Debt Instrument Twenty Four [Member]
Secured financing agreements, net	$ 8,723
Interest Rate	0.30%
Single Family Rental [Member] \| Debt Instrument Twenty Five [Member]
Secured financing agreements, net	$ 7,344
Interest Rate	0.30%
Multifamily [Member] \| Mezzanine Loan Portfolio [Member]
Secured financing agreements, net	$ 59,914
Interest Rate	0.30%
Multifamily [Member] \| Debt Instrument One [Member] \| Mezzanine Loan Portfolio [Member] \| Wilmington, DE [Member]
Secured financing agreements, net	$ 6,353
Interest Rate	0.30%
Multifamily [Member] \| Debt Instrument Two [Member] \| Mezzanine Loan Portfolio [Member] \| White Marsh, MD [Member]
Secured financing agreements, net	$ 5,881
Interest Rate	0.30%
Multifamily [Member] \| Debt Instrument Three [Member] \| Mezzanine Loan Portfolio [Member] \| Philadelphia, PA [Member]
Secured financing agreements, net	$ 4,523
Interest Rate	0.30%
Multifamily [Member] \| Debt Instrument Four [Member] \| Mezzanine Loan Portfolio [Member] \| Daytona Beach, FL [Member]
Secured financing agreements, net	$ 4,179
Interest Rate	0.30%
Multifamily [Member] \| Debt Instrument Five [Member] \| Mezzanine Loan Portfolio [Member] \| Laurel, MD [Member]
Secured financing agreements, net	$ 3,390
Interest Rate	0.30%
Multifamily [Member] \| Debt Instrument Six [Member] \| Mezzanine Loan Portfolio [Member] \| Temple Hills, MD [Member]
Secured financing agreements, net	$ 3,348
Interest Rate	0.30%
Multifamily [Member] \| Debt Instrument Seven [Member] \| Mezzanine Loan Portfolio [Member] \| Temple Hills, MD [Member]
Secured financing agreements, net	$ 2,454
Interest Rate	0.30%
Multifamily [Member] \| Debt Instrument Eight [Member] \| Mezzanine Loan Portfolio [Member] \| Lakewood, NJ [Member]
Secured financing agreements, net	$ 2,264
Interest Rate	0.30%
Multifamily [Member] \| Debt Instrument Nine [Member] \| Mezzanine Loan Portfolio [Member] \| North Aurora, IL [Member]
Secured financing agreements, net	$ 2,215
Interest Rate	0.30%
Multifamily [Member] \| Debt Instrument Ten [Member] \| Mezzanine Loan Portfolio [Member] \| Rosedale, MD [Member]
Secured financing agreements, net	$ 2,026
Interest Rate	0.30%
Multifamily [Member] \| Debt Instrument Eleven [Member] \| Mezzanine Loan Portfolio [Member] \| Cockeysville, MD [Member]
Secured financing agreements, net	$ 1,836
Interest Rate	0.30%
Multifamily [Member] \| Debt Instrument Twelve [Member] \| Mezzanine Loan Portfolio [Member] \| Laurel, MD [Member]
Secured financing agreements, net	$ 1,763
Interest Rate	0.30%
Multifamily [Member] \| Debt Instrument Thirteen [Member] \| Mezzanine Loan Portfolio [Member] \| Vancouver, WA [Member]
Secured financing agreements, net	$ 1,307
Interest Rate	0.30%
Multifamily [Member] \| Debt Instrument Fourteen [Member] \| Mezzanine Loan Portfolio [Member] \| Tyler, TX [Member]
Secured financing agreements, net	$ 918
Interest Rate	0.30%
Multifamily [Member] \| Debt Instrument Fifteen [Member] \| Mezzanine Loan Portfolio [Member] \| Las Vegas, NV [Member]
Secured financing agreements, net	$ 728
Interest Rate	0.30%
Multifamily [Member] \| Debt Instrument Sixteen [Member] \| Mezzanine Loan Portfolio [Member] \| Atlanta, GA [Member]
Secured financing agreements, net	$ 662
Interest Rate	0.30%

Single Family Rental [Member]