Repurchase Agreements - Summary of Repurchase Agreements Accounted as Secured Borrowings (Details) $ in Thousands	Sep. 30, 2020 USD ($)
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	$ 108,950
Securities pledged for Repurchase Agreements	116,931
Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	108,950
Securities pledged for Repurchase Agreements	116,931
Up to one year
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	0
Securities pledged for Repurchase Agreements	0
One to three years
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	0
Securities pledged for Repurchase Agreements	0
Three to five years
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	0
Securities pledged for Repurchase Agreements	0
Five to ten years
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	0
Securities pledged for Repurchase Agreements	0
Beyond ten years
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	0
Securities pledged for Repurchase Agreements	0
Federal agency collateralized mortgage obligations
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements	55,336
Federal agency collateralized mortgage obligations | Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements	55,336
Federal agency collateralized mortgage obligations | Up to one year
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements	0
Federal agency collateralized mortgage obligations | One to three years
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements	0
Federal agency collateralized mortgage obligations | Three to five years
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements	0
Federal agency collateralized mortgage obligations | Five to ten years
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements	0
Federal agency collateralized mortgage obligations | Beyond ten years
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements	0
Federal agency mortgage-backed pools
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements	61,595
Federal agency mortgage-backed pools | Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements	61,595
Federal agency mortgage-backed pools | Up to one year
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements	0
Federal agency mortgage-backed pools | One to three years
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements	0
Federal agency mortgage-backed pools | Three to five years
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements	0
Federal agency mortgage-backed pools | Five to ten years
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements	0
Federal agency mortgage-backed pools | Beyond ten years
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements	$ 0