Mergers and acquisitions - Consideration for FNB Financial Corp. (Details) - FNB Financial Corp. - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
Feb. 14, 2020	Dec. 31, 2020
Business Combination, Consideration Transferred [Abstract]
Net shares issued (in shares)	954,797
Purchase price per share (in dollars per share)	$ 36.70
Value of stock consideration	$ 35,041
Cash consideration paid	15,001
Total purchase price	50,042
Preliminary fair value of net assets acquired	43,723
Goodwill resulting from merger	$ 6,319	$ 6,319

Business Acquisition, Transaction Value

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Business Acquisition, Value of Stock Consideration

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Number of shares of equity interests issued or issuable to acquire entity.

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Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

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Amount recognized as of the acquisition date for the identifiable assets acquired in excess of (less than) the aggregate liabilities assumed.

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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