Fair value estimates - Carrying and Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Investment securities:
Available-for-sale	$ 271,378	$ 272,548
Common equity securities	189
Held-to-maturity	9,104	9,547
Loans held for sale		106
Mortgage servicing rights	719	728
Other assets	66,644	64,469
Carrying Value
Financial assets:
Cash and cash equivalents	26,775	37,488
Investment securities:
Available-for-sale	271,378	272,548
Common equity securities	189
Held-to-maturity	9,028	9,274
Loans held for sale		106
Net loans	1,706,063	1,674,105
Accrued interest receivable	6,482	6,936
Mortgage servicing rights	719	728
Restricted equity securities	10,231	8,562
Interest rate swaps	148	655
Total assets	2,031,013	2,010,402
Financial liabilities:
Deposits	1,720,018	1,719,018
Short-term borrowings	142,500	123,675
Long-term debt	49,265	49,734
Accrued interest payable	518	497
Interest rate swap	161	733
Total liabilities	1,912,462	1,893,657
Fair Value
Financial assets:
Cash and cash equivalents	26,775	37,488
Investment securities:
Available-for-sale	271,378	272,548
Common equity securities	189
Held-to-maturity	9,104	9,547
Loans held for sale		106
Net loans	1,666,717	1,645,292
Accrued interest receivable	6,482	6,936
Mortgage servicing rights	1,618	1,638
Restricted equity securities	10,231	8,562
Other assets		2,249
Interest rate swaps	148	655
Total assets	1,992,642	1,985,021
Financial liabilities:
Deposits	1,715,633	1,666,284
Short-term borrowings	142,500	123,675
Long-term debt	49,482	50,147
Accrued interest payable	518	497
Interest rate swap	161	733
Total liabilities	1,908,294	1,841,336
Level 1
Financial assets:
Cash and cash equivalents	26,775	37,488
Investment securities:
Available-for-sale	25,476	19,860
Common equity securities	189
Level 2
Investment securities:
Available-for-sale	245,902	252,688
Held-to-maturity	9,104	9,547
Loans held for sale		106
Accrued interest receivable	6,482	6,936
Mortgage servicing rights	1,618	1,638
Restricted equity securities	10,231	8,562
Interest rate swaps	148	655
Financial liabilities:
Deposits	1,715,633	1,666,284
Short-term borrowings	142,500	123,675
Long-term debt	49,482	50,147
Accrued interest payable	518	497
Interest rate swap	161	733
Level 3
Investment securities:
Net loans	$ 1,666,717	1,645,292
Other assets		$ 2,249

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents accrued interest payable as of the balance sheet date.

No definition available.