Note 7 - Long-lived Assets Impairment Loss (Details Textual) - USD ($)	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Impairment Of Oil And Gas Cost Properties	$ 0	$ 0	$ 88,764	$ 508,964

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