Borrowings - Repurchase agreements accounted for as secured borrowings (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 91,384	$ 148,609
Secured Debt
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 91,384	$ 148,609
Repurchase liability weighted average interest rate	5.59%	4.18%
Secured Debt | US Treasury Securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 43,592	$ 48,670
Repurchase liability weighted average interest rate	5.61%	4.01%
Secured Debt | US Treasury Securities | Within 30 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 16,931	$ 410
Repurchase liability weighted average interest rate	5.56%	4.40%
Secured Debt | US Treasury Securities | After 30 to 90 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 18,369	$ 30,739
Repurchase liability weighted average interest rate	5.60%	3.79%
Secured Debt | US Treasury Securities | After 90 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 8,292	$ 17,521
Repurchase liability weighted average interest rate	5.73%	4.39%
Secured Debt | Mortgage Backed Securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 47,565	$ 99,775
Repurchase liability weighted average interest rate	5.58%	4.26%
Secured Debt | Mortgage Backed Securities | Within 30 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 27,171	$ 98,984
Repurchase liability weighted average interest rate	5.49%	4.27%
Secured Debt | Mortgage Backed Securities | After 30 to 90 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 20,394	$ 791
Repurchase liability weighted average interest rate	5.71%	3.27%
Secured Debt | CMO
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 227	$ 164
Repurchase liability weighted average interest rate	5.25%	4.25%
Secured Debt | CMO | Within 30 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 227	$ 164
Repurchase liability weighted average interest rate	5.25%	4.25%