Fair value of financial instruments - Carrying and Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Investment securities:
Available-for-sale	$ 272,548	$ 259,410
Held-to-maturity	9,547	10,714
Loans held for sale	106
Mortgage servicing rights	728	698
Other assets	64,469	65,501
Carrying Value
Financial assets:
Cash and cash equivalents	37,488	39,941
Investment securities:
Available-for-sale	272,548	259,410
Held-to-maturity	9,274	10,517
Loans held for sale	106
Net loans	1,674,105	1,517,004
Accrued interest receivable	6,936	6,228
Mortgage servicing rights	728	698
Restricted equity securities	8,562	7,051
Interest rate swaps	655
Total assets	2,010,402	1,840,849
Financial liabilities:
Deposits	1,719,018	1,588,757
Short-term borrowings	123,675	82,700
Long-term debt	49,734	58,134
Accrued interest payable	497	462
Interest rate swaps	(733)
Total liabilities	1,893,657	1,730,053
Fair Value
Financial assets:
Cash and cash equivalents	37,488	39,941
Investment securities:
Available-for-sale	272,548	259,410
Held-to-maturity	9,547	10,714
Loans held for sale	106
Net loans	1,645,292	1,507,936
Accrued interest receivable	6,936	6,228
Mortgage servicing rights	1,638	1,587
Restricted equity securities	8,562	7,051
Other assets	2,249
Interest rate swaps	655
Total assets	1,985,021	1,832,867
Financial liabilities:
Deposits	1,666,284	1,587,701
Short-term borrowings	123,675	82,700
Long-term debt	50,147	58,987
Accrued interest payable	497	462
Interest rate swaps	(733)
Total liabilities	1,841,336	1,729,850
Level 1
Financial assets:
Cash and cash equivalents	37,488	39,941
Investment securities:
Available-for-sale	19,860	7,438
Level 2
Investment securities:
Available-for-sale	252,688	251,972
Held-to-maturity	9,547	10,714
Loans held for sale	106
Accrued interest receivable	6,936	6,228
Mortgage servicing rights	1,638	1,587
Restricted equity securities	8,562	7,051
Interest rate swaps	655
Financial liabilities:
Deposits	1,666,284	1,587,701
Short-term borrowings	123,675	82,700
Long-term debt	50,147	58,987
Accrued interest payable	497	462
Interest rate swaps	(733)
Level 3
Investment securities:
Net loans	1,645,292	$ 1,507,936
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.