Cash and Due From Banks (Additional Information) (Detail) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Cash And Due From Banks [Abstract]
Cash and due from banks	$ 30,625,000	$ 4,009,000
Cash collateral from counterparties	$ 525,000	$ 0

For banks and other depository institutions: Includes cash on hand (currency and coin), cash items in process of collection, noninterest bearing deposits due from other financial institutions (including corporate credit unions), and noninterest bearing balances with the Federal Reserve Banks, Federal Home Loan Banks and central banks.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(1))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Name:	us-gaap_CashAndDueFromBanks
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant