Regulatory Capital Requirements - Components of Regulatory Capital (Parenthetical) (Detail)	Sep. 30, 2019	Dec. 31, 2018
Home Savings [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Allowance for loan and allowance for unfunded lending commitments, percentage of risk-weighted assets	1.25%	1.25%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration