EMPLOYEE BENEFIT PLAN - Trading results related to SERP (Details 1) (Non-qualified Supplemental Retirement Plan ("SERP"), USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Non-qualified Supplemental Retirement Plan ("SERP")
Multiemployer Plans [Line Item]
Gains (losses), net	$ 204	$ 184

This element represents the amount of trading gains (losses) of plan assets under the defined benefit plan.

No definition available.

Name:	res_DefinedBenefitPlanTradingGainsLosses
Namespace Prefix:	res_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration