Note 9 - Incentive and Retirement Plans - Cash-based Awards Issued and Outstanding (Details)	12 Months Ended
Dec. 31, 2025 USD ($)
Balance, Targeted Performance-Based Cash	$ 0
Balance, Vested	0
Issued, Targeted Performance-Based Cash	432,245
Issued, Vested	$ 0
Issued, Vesting Date	Jan. 01, 2028
Balance, Targeted Performance-Based Cash	$ 432,245
Balance, Vested	$ 0

Amount of commitment made during the period to pay deferred cash remuneration.

No definition available.

Name:	nuvr_DeferredCompensationArrangementWithIndividualCashAwardGrantedIssuedInPeriod
Namespace Prefix:	nuvr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Vesting date of commitment made to pay deferred cash remuneration.

No definition available.

Name:	nuvr_DeferredCompensationArrangementWithIndividualCashAwardGrantedVestingDate
Namespace Prefix:	nuvr_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

Amount of commitment made to pay deferred cash remuneration that has vested.

No definition available.

Name:	nuvr_DeferredCompensationArrangementWithIndividualCashAwardVestedAmount
Namespace Prefix:	nuvr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of commitment made during period to pay deferred cash remuneration that has vested.

No definition available.

Name:	nuvr_DeferredCompensationArrangementWithIndividualCashAwardVestedIssuedInPeriod
Namespace Prefix:	nuvr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of commitment made to pay deferred cash remuneration.

No definition available.

Name:	us-gaap_DeferredCompensationArrangementWithIndividualCashAwardGrantedAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant