Commitments and contingencies - Allowance for Credit Losses on Unfunded Commitments (Details) - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Dec. 31, 2020 |
Jan. 01, 2020 |
|
| Commitments and Contingencies [Roll Forward] | ||
| Balance at beginning of period | $ 31,139 | |
| Balance at end of period | 170,389 | |
| Unfunded Commitments | ||
| Commitments and Contingencies [Roll Forward] | ||
| Balance at beginning of period | 0 | |
| Impact of CECL adoption on provision for credit losses on unfunded commitments | $ 2,947 | |
| Increase in provision for credit losses from unfunded commitments acquired in business combination | 10,499 | |
| Provision for credit losses on unfunded commitments | 2,932 | |
| Balance at end of period | $ 16,378 |