Annual report pursuant to Section 13 and 15(d)

Acquisition Activity (Details Textual)

v3.10.0.1
Acquisition Activity (Details Textual)
$ in Thousands
 1 Months Ended 12 Months Ended
Jan. 23, 2019
USD ($)
Jul. 25, 2018
USD ($)
shares
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Dec. 17, 2018
USD ($)
May 31, 2004
USD ($)
Business Acquisition [Line Items]            
Payments to Acquire Businesses, Net of Cash Acquired     $ 8,689 $ 0    
Business Combination Financial Information Assets Reported by the Acquiree     174,900      
Business Combination Financial Information Loans Receivables Reported by the Acquiree     91,500      
Business Combination Financial Information Deposits Reported by the Acquiree     143,800      
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets     145,930      
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities     130,313      
Business Acquisition, Transaction Costs     $ 1,800      
Number Of Banking Centers     19      
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Long-term Debt     $ 4,124      
First Personal Bank [Member]            
Business Acquisition [Line Items]            
Business Acquisition Description Of Consideration Paid     Merger, each First Personal stockholder holding 100 or more shares of First Personal common stock received fixed consideration of (i) 0.1246 shares of Bancorp common stock, and (ii) $6.67 per share in cash for each outstanding share of First Personal common stock. Stockholders holding less than 100 shares of First Personal common stock received $12.12 in cash and no stock consideration for each outstanding share of First Personal common stock. Any fractional shares of Bancorp common stock that a First Personal stockholder would have otherwise received in the First Personal Merger were cashed out in the amount of such fraction multiplied by $42.95.      
Business Combination, Consideration Transferred   $ 15,600        
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares | shares   161,875        
Payments to Acquire Businesses, Net of Cash Acquired   $ 8,700        
AJS Bancorp Inc [Member]            
Business Acquisition [Line Items]            
Business Acquisition Description Of Consideration Paid     each AJSB stockholder holding 100 or more shares of AJSB common stock received fixed consideration of (i) 0.2030 shares of NWIN common stock, and (ii) $7.20 per share in cash for each outstanding share of AJSB’s common stock. Stockholders holding less than 100 shares of AJSB common stock received $16.00 in cash and no stock consideration for each outstanding share of AJSB common stock. Any fractional shares of NWIN common stock that an AJSB stockholder would have otherwise received in the AJSB Merger were cashed out in the amount of such fraction multiplied by $43.01.      
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed Total Loans     $ 860,200      
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities     $ 1,100,000      
First Personal Statutory Trust I [Member]            
Business Acquisition [Line Items]            
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Long-term Debt           $ 4,124
Equity Securities Description of Variable Rate Basis     LIBOR plus 275 basis points      
Business Acquisition Date of Expiration Agreement     Jun. 17, 2034      
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed Debt Redeemed         $ 4,124  
AJSB [Member]            
Business Acquisition [Line Items]            
Business Combination, Consideration Transferred $ 34,200          
Payments to Acquire Businesses, Net of Cash Acquired     $ 15,400      
Business Acquisition, Transaction Costs     $ 245      
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable Fair Value Method     416,478