Borrowings - Repurchase agreements accounted for as secured borrowings (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 148,609	$ 91,603
Secured Debt
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 148,609	$ 91,603
Repurchase liability weighted average interest rate	4.18%	0.26%
US Treasury Securities | Secured Debt
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 48,670	$ 78,869
Repurchase liability weighted average interest rate	4.01%	0.26%
US Treasury Securities | Within 30 days | Secured Debt
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 410	$ 19,538
Repurchase liability weighted average interest rate	4.40%	0.30%
US Treasury Securities | After 30 to 90 days | Secured Debt
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 30,739	$ 30,295
Repurchase liability weighted average interest rate	3.79%	0.21%
US Treasury Securities | After 90 days | Secured Debt
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 17,521	$ 29,036
Repurchase liability weighted average interest rate	4.39%	0.29%
Mortgage Backed Securities | Secured Debt
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 99,775	$ 12,455
Repurchase liability weighted average interest rate	4.26%	0.26%
Mortgage Backed Securities | Within 30 days | Secured Debt
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 98,984	$ 11,733
Repurchase liability weighted average interest rate	4.27%	0.26%
Mortgage Backed Securities | After 30 to 90 days | Secured Debt
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 791	$ 0
Repurchase liability weighted average interest rate	3.27%	0.00%
Mortgage Backed Securities | After 90 days | Secured Debt
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 0	$ 722
Repurchase liability weighted average interest rate	0.00%	0.16%
CMO | Secured Debt
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 164	$ 279
Repurchase liability weighted average interest rate	4.25%	0.25%
CMO | Within 30 days | Secured Debt
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 164	$ 279
Repurchase liability weighted average interest rate	4.25%	0.25%