Note 10 - Long-lived Assets Impairment Loss (Details Textual) - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Impairment Of Oil And Gas Cost Properties	$ 832,651	$ 426,822

The expense recorded to reduce the cost of oil and gas assets consisting of proved properties to the estimated future value of the production from these properties.

No definition available.

Name:	rsrv_ImpairmentOfOilAndGasCostProperties
Namespace Prefix:	rsrv_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration