ACQUISITIONS - LSHC (Details)
Dec. 31, 2014
USD ($)
item
shares
Dec. 31, 2016
USD ($)
Nov. 10, 2016
USD ($)
Dec. 31, 2015
USD ($)
Business Acquisition [Line Items]        
Goodwill   $ 48,836,000   $ 46,519,000
Intangibles     $ 2,300,000  
LSHC | Banking        
Business Acquisition [Line Items]        
Office location acquired | item 10      
LSHC | Loan Production        
Business Acquisition [Line Items]        
Office location acquired | item 3      
LSHC | Branch        
Business Acquisition [Line Items]        
Office location acquired | item 1      
Heartland | LSHC        
Business Acquisition [Line Items]        
Amortization period 10 years      
Amount of trust preferred debentures $ 40,000,000      
Fair value of the noncontrolling interest $ 500,000      
Number of mortgage origination joint ventures | item 2      
Ownership interest (as a percentage) 51.00%      
Heartland | LSHC | Core deposits        
Business Acquisition [Line Items]        
Intangibles $ 3,400,000      
LFC | LSHC        
Business Acquisition [Line Items]        
Total Purchase consideration 67,300,000      
Consideration paid in cash $ 20,100,000      
Number of common stock shares issued | shares 2,224,091      
Accrual of other liabilities fair value $ 530,000      
Number of years of earnings 2 years      
Adjusted net income (as a percentage) 50.00%      
Minimum earnings $ 9,100,000      
Contingent consideration   $ 350,000   $ 180,000