Note 5 - Disclosures About Fair Value of Assets and Liabilities - Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Reported Value Measurement [Member]
Financial assets
Cash and due from banks	$ 1,757	$ 1,085
Interest-earning demand deposits	3,439	2,997
Federal funds sold	12,269	11,711
Loans, net	92,415	100,746
Federal Home Loan Bank stock	468	468
Accrued interest receivable	259	267
Servicing rights	1,144	937
Interest-earning time deposits in banks		744
Financial liabilities
Deposits	93,239	101,688
Advances from the Federal Home Loan Bank	9,027	9,027
Accrued interest payable	15	30
Estimate of Fair Value Measurement [Member]
Financial assets
Cash and due from banks	1,757	1,085
Interest-earning demand deposits	3,439	2,997
Federal funds sold	12,269	11,711
Loans, net	91,580	100,273
Federal Home Loan Bank stock	468	468
Accrued interest receivable	259	267
Servicing rights	1,144	937
Interest-earning time deposits in banks		744
Financial liabilities
Deposits	92,390	101,603
Advances from the Federal Home Loan Bank	8,966	9,024
Accrued interest payable	15	30
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member]
Financial assets
Cash and due from banks	1,757	1,085
Interest-earning demand deposits	3,439	2,997
Federal funds sold	12,269	11,711
Loans, net
Federal Home Loan Bank stock
Accrued interest receivable
Servicing rights
Interest-earning time deposits in banks
Financial liabilities
Deposits	57,985	61,767
Advances from the Federal Home Loan Bank
Accrued interest payable
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 2 [Member]
Financial assets
Cash and due from banks
Interest-earning demand deposits
Federal funds sold
Loans, net
Federal Home Loan Bank stock	468	468
Accrued interest receivable	259	267
Servicing rights
Interest-earning time deposits in banks		744
Financial liabilities
Deposits	34,405	39,836
Advances from the Federal Home Loan Bank	8,966	9,024
Accrued interest payable	15	30
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member]
Financial assets
Cash and due from banks
Interest-earning demand deposits
Federal funds sold
Loans, net	91,580	100,273
Federal Home Loan Bank stock
Accrued interest receivable
Servicing rights	1,144	937
Interest-earning time deposits in banks
Financial liabilities
Deposits
Advances from the Federal Home Loan Bank
Accrued interest payable

New Bancorp, Inc. 10-Q