PRIVATE PLACEMENT (Details) - Private Placement - USD ($)		6 Months Ended
Dec. 15, 2020	Jun. 30, 2021
Subsidiary, Sale of Stock [Line Items]
Number of warrants to purchase shares issued	275,000
Price of warrants	$ 10.00
Aggregate purchase price	$ 2,750,000
Private Placement Warrants
Subsidiary, Sale of Stock [Line Items]
Number of warrants to purchase shares issued		275,000
Price of warrants		$ 10.00
Aggregate purchase price		$ 2,750,000
Number of shares in a unit		1
Number of warrants in a unit		1
Number of shares per warrant		1
Exercise price of warrant		$ 11.50

Price per share or per unit of warrants or rights outstanding.

No definition available.

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Namespace Prefix:	rsvr_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of shares in a unit.

+ References

No definition available.

+ Details

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Namespace Prefix:	rsvr_
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Balance Type:	na
Period Type:	duration

- Definition

Represents the number of warrants in a unit.

+ References

No definition available.

+ Details

Name:	rsvr_NumberOfWarrantsIssuedPerUnit
Namespace Prefix:	rsvr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Number of securities into which each warrant or right may be converted. For example, but not limited to, each warrant may be converted into two shares.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

+ References

+ Details

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash inflow from issuance of rights to purchase common shares at predetermined price (usually issued together with corporate debt).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585

+ Details

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

- Definition

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.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Details

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- Details

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