EARNINGS PER SHARE (Detail Textuals) (Restricted Shares, USD $)	3 Months Ended	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Restricted Shares
Earnings Per Share [Line Items]
Reduction in reported basic earnings per share under the two class method	$ 0.02	$ 0.01	$ 0.06	$ 0.04

Represents the amount of reduction in basic earining per share.

No definition available.

Name:	res_ReductionInBasicEarningsPerShare
Namespace Prefix:	res_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration