Borrowings - Repurchase agreements accounted for as secured borrowings (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 55,360	$ 91,384
Secured Debt
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	55,360	91,384
Secured Debt | US Treasury Securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	35,838	43,592
Secured Debt | US Treasury Securities | Within 30 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	21,956	16,931
Secured Debt | US Treasury Securities | After 30 to 90 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	13,882	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	19,522	47,565
Secured Debt | Mortgage Backed Securities - federal agencies | Within 30 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	5,206	27,171
Secured Debt | Mortgage Backed Securities - federal agencies | After 30 to 90 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	14,316	20,394
Secured Debt | CMO
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	0	227
Secured Debt | CMO | Within 30 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase liability	$ 0	$ 227