Borrowings - Repurchase agreements accounted for as secured borrowings (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Assets Sold under Agreements to Repurchase
Repurchase liability	$ 70,925	$ 91,603
Secured Debt
Assets Sold under Agreements to Repurchase
Repurchase liability	70,925	91,603
US Treasury Securities | Secured Debt
Assets Sold under Agreements to Repurchase
Repurchase liability	59,544	78,869
US Treasury Securities | Within 30 days | Secured Debt
Assets Sold under Agreements to Repurchase
Repurchase liability	14,139	19,538
US Treasury Securities | After 30 to 90 days | Secured Debt
Assets Sold under Agreements to Repurchase
Repurchase liability	18,198	30,295
US Treasury Securities | After 90 days | Secured Debt
Assets Sold under Agreements to Repurchase
Repurchase liability	27,207	29,036
Mortgage Backed Securities | Secured Debt
Assets Sold under Agreements to Repurchase
Repurchase liability	11,381	12,455
Mortgage Backed Securities | Within 30 days | Secured Debt
Assets Sold under Agreements to Repurchase
Repurchase liability	10,534	11,733
Mortgage Backed Securities | After 30 to 90 days | Secured Debt
Assets Sold under Agreements to Repurchase
Repurchase liability	847	0
Mortgage Backed Securities | After 90 days | Secured Debt
Assets Sold under Agreements to Repurchase
Repurchase liability	0	722
CMO | Secured Debt
Assets Sold under Agreements to Repurchase
Repurchase liability	0	279
CMO | Within 30 days | Secured Debt
Assets Sold under Agreements to Repurchase
Repurchase liability	$ 0	$ 279