Note 6 - FDIC Loss Share Agreements (Details Textual)
$ in Thousands
3 Months Ended 9 Months Ended
Aug. 26, 2016
USD ($)
Sep. 30, 2016
USD ($)
Sep. 30, 2016
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Loans and Leases Receivable, Gross, Carrying Amount, Covered       $ 0 $ 17,651  
Other Real Estate, Covered       $ 0 1,240 $ 3,011
After Tax Charge Resulted from Early Termination under the FDIC Loss Share Agreements   $ 15        
Reclassification of Loans and Leases Receivable from Covered to Non-covered     $ 15,100      
Reclassification of Other Real Estate Owned from Covered to Non-covered     $ 380      
FDIC Indemnification Asset True Up Amount         $ 5,700  
Bank [Member]            
Payments for Early Termination under the FDIC Loss Share Agreements $ 4,400          
Citizens South Banking Corporation [Member]            
Number of Purchase and Assumption Agreeements         2  
Loans and Leases Receivable, Gross, Carrying Amount, Covered         $ 17,700  
Other Real Estate, Covered         $ 1,200