Note 2 - Business Combinations - Summary of Estimated Fair Value of Assets and Liabilities Acquired (Details) - USD ($)
Oct. 31, 2015
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Goodwill   $ 50,771,000 $ 50,686,000 $ 28,834,000
Reunion Bank of Florida [Member]        
Cash and cash equivalents $ 3,136,000      
Investment securities 19,126,000      
Loans 258,414,000      
Allowance for loan losses      
Net loans 258,414,000      
Premises and equipment, net 3,922,000      
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill 1,539,000      
Bank-owned life insurance 4,098,000      
Other real estate and repossessions 92,000      
Other assets 19,368,000      
Total assets 309,695,000      
Non-interest bearing deposits 80,382,000      
Interest-bearing deposits 197,277,000      
Total deposits 277,659,000      
Other liabilities 9,477,000      
Total liabilities 287,136,000      
Net identifiable assets acquired over liabilities assumed 22,559,000      
Goodwill 20,639,000      
Net assets acquired over liabilities assumed $ 43,198,000      
Shares of common stock issued (in shares) 1,339,129      
Estimated value per share of the Company's stock (in dollars per share) $ 25.11      
Fair value of Company stock issued $ 33,626,000      
Cash paid for shares and in lieu of fractional shares 7,369,000      
Value of assumed stock options 2,203,000      
Fair value of total consideration transferred 43,198,000      
Reunion Bank of Florida [Member] | Measured by Acquired Company [Member]        
Cash and cash equivalents 3,136,000      
Investment securities 19,261,000      
Loans 265,492,000      
Allowance for loan losses 2,429,000      
Net loans 263,063,000      
Premises and equipment, net 3,922,000      
Bank-owned life insurance 4,098,000      
Other real estate and repossessions 92,000      
Other assets 21,371,000      
Total assets 314,943,000      
Non-interest bearing deposits 80,382,000      
Interest-bearing deposits 196,957,000      
Total deposits 277,339,000      
Other liabilities 10,561,000      
Total liabilities 287,900,000      
Net identifiable assets acquired over liabilities assumed 27,043,000      
Net assets acquired over liabilities assumed 27,043,000      
Reunion Bank of Florida [Member] | Fair Value Adjustments [Member]        
Investment securities [1] (135,000)      
Loans [2] (7,078,000)      
Allowance for loan losses [3] (2,429,000)      
Net loans (4,649,000)      
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill [4] 1,539,000      
Bank-owned life insurance      
Other real estate and repossessions      
Other assets [5] (2,003,000)      
Total assets (5,248,000)      
Non-interest bearing deposits      
Interest-bearing deposits 320,000      
Total deposits 320,000      
Other liabilities [5] (1,084,000)      
Total liabilities (764,000)      
Net identifiable assets acquired over liabilities assumed (4,484,000)      
Goodwill 20,639,000      
Net assets acquired over liabilities assumed $ 16,155,000      
[1] Adjustment reflects fair value adjustments of the available-for-sale portfolio at acquisition date.
[2] Adjustment reflects the fair value adjustments based on the Company's evaluation of the acquired loan portfolio.
[3] Adjustment reflects the elimination of Reunion's allowance for loan losses.
[4] Adjustment reflects the recording of core deposit intangible asset.
[5] Adjustment to record the deferred tax asset created by purchase adjustments and reclassify income tax payable accounts.