Employee Benefit Plans (Detail Textuals 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Benefit Plans
Minimum percentage of annual contribution per employee	1.00%
Maximum percentage of annual contribution per employee	25.00%
Percentage of employer matching contribution	50.00%
Threshold limit percentage of employee compensation	6.00%
Maximum period of vesting in contribution of employer	after three years of service
Employer contribution	$ 6,970	$ 5,451	$ 5,088

Minimum percentage of employee gross pay, by the terms of the plan, that the employer may contribute to a defined contribution plan.

No definition available.

Name:	res_DefinedContributionPlanMinimumAnnualContributionPerEmployeePercent
Namespace Prefix:	res_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

This element represents the threshold limit in percentage of employees' compensation.

No definition available.

Name:	res_DefinedContributionPlanThresholdLimitPercentageOfEmployeeCompensation
Namespace Prefix:	res_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

This element represents the maximum period of vesting in contribution of employer.

No definition available.

Name:	res_MaximumPeriodOfVestingInContributionOfEmployer
Namespace Prefix:	res_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_CompensationAndRetirementDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of discretionary contributions made by an employer to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration