Borrowings - Repurchase agreements accounted for as secured borrowings (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 66,090	$ 91,384
Secured Debt
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	66,090	91,384
Secured Debt | US Treasury Securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	49,085	43,592
Secured Debt | US Treasury Securities | Within 30 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	30,581	16,931
Secured Debt | US Treasury Securities | After 30 to 90 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	18,504	18,369
Secured Debt | US Treasury Securities | After 90 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	0	8,292
Secured Debt | Mortgage Backed Securities - federal agencies
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	16,778	47,565
Secured Debt | Mortgage Backed Securities - federal agencies | Within 30 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	11,550	27,171
Secured Debt | Mortgage Backed Securities - federal agencies | After 30 to 90 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	5,228	20,394
Secured Debt | CMO
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	227	227
Secured Debt | CMO | Within 30 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 227	$ 227