Supplemental Schedules of Oil and Gas Information (Details Textual)	12 Months Ended
Dec. 31, 2016 bbl MMcf	Dec. 31, 2015 bbl MMcf
Oil and Condensate (Bbls) [Member]
Proved Developed and Undeveloped Reserves Production Royalty \| bbl	17,423	21,507
Gas (MCF) [Member]
Proved Developed and Undeveloped Reserves Production Royalty \| MMcf	335,081	361,304

Company's share of production of proved reserves from net royalty interests.

No definition available.

Name:	rsrv_ProvedDevelopedAndUndevelopedReservesProductionRoyalty
Namespace Prefix:	rsrv_
Data Type:	num:volumeItemType
Balance Type:	na
Period Type:	duration