Note 7 - Use of Special Purpose Entities and Variable Interest Entities (Details) - Key Details of Financing VIEs (Parentheticals)
12 Months Ended
Dec. 31, 2013
Multi-Family Collateralized Mortgage Backed Securities [Member] | Minimum [Member]
 
Variable Interest Entity [Line Items]  
Pass-through rate 5.35%
Collateralized Recourse Financing [Member] | Minimum [Member]
 
Variable Interest Entity [Line Items]  
Pass-through rate 5.25%
Collateralized Recourse Financing [Member] | Maximum [Member]
 
Variable Interest Entity [Line Items]  
Pass-through rate 6.50%
Residential Distressed Mortgage Loan Securitization [Member] | Minimum [Member]
 
Variable Interest Entity [Line Items]  
Pass-through rate 4.25%
Residential Distressed Mortgage Loan Securitization [Member] | Maximum [Member]
 
Variable Interest Entity [Line Items]  
Pass-through rate 4.85%