Cash and Due From Bank - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Cash and Due from Banks [Abstract]
Average collected cash balances with commercial banks	$ 19.3	$ 16.3

Average amount of collected cash balances with commercial banks the Federal Home Loan Banks (FHLBanks) maintain in return for certain services.

No definition available.

Name:	us-gaap_AverageCollectedCashBalancesWithCommercialBanksFederalHomeLoanBank
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration