Related party transactions - Narrative (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Related Party Transaction [Line Items] | |||
| Deposits from related parties | $ 245,084 | $ 238,781 | |
| Lease expense | $ 5,019 | ||
| Aviation Time Sharing Agreement | |||
| Related Party Transaction [Line Items] | |||
| Payments to related party | 161 | 266 | 208 |
| Certain Executive Officers, Certain Management and Directors and Their Associates | Unfunded Loan Commitment | |||
| Related Party Transaction [Line Items] | |||
| Unfunded commitments | 23,059 | 19,404 | |
| Director | |||
| Related Party Transaction [Line Items] | |||
| Unamortized leasehold improvements | 53 | 86 | |
| Operating lease expense | $ 510 | $ 509 | |
| Lease expense | $ 516 | ||