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.

+ Details

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

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953676-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Pre-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=rive_CommercialRealEstateOwnerOccupiedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=rive_ResidentialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Loans Receivable, Credit Quality for Loans and the Allowance for Loan Losses - Schedule of Number of Loans and Recorded Investment in TDRs (Detail) $ in Thousands	3 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2016 Contract	Jun. 30, 2016 Contract	Jun. 30, 2015 USD ($) Contract	Dec. 31, 2015 Contract
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructurings, Number of Contracts \| Contract	0	29		32
Commercial Real Estate Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructurings, Number of Contracts \| Contract			1
Troubled Debt Restructurings, Pre-Modification Outstanding Recorded Investment			$ 149
Troubled Debt Restructurings, Post-Modification Outstanding Recorded Investment			$ 149
Residential Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructurings, Number of Contracts \| Contract			3
Troubled Debt Restructurings, Pre-Modification Outstanding Recorded Investment			$ 473
Troubled Debt Restructurings, Post-Modification Outstanding Recorded Investment			$ 473