XML 39 R28.htm IDEA: XBRL DOCUMENT
v3.19.3

EMPLOYEE BENEFIT PLAN (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2019
EMPLOYEE BENEFIT PLAN |
Schedule of net periodic benefit cost | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Three months ended | ​ | Nine months ended
​ | ​ | September 30, | ​ | September 30,
(in thousands) |  | 2019 |  | 2018 |  | 2019 |  | 2018
Interest cost | ​ | $ | 490 | ​ | $ | 458 | ​ | $ | 1,470 | ​ | $ | 1,374
Expected return on plan assets | ​ |  | (649) | ​ |  | (710) | ​ |  | (1,949) | ​ |  | (2,128)
Amortization of net losses | ​ |  | 229 | ​ |  | 206 | ​ |  | 689 | ​ |  | 618
Net periodic benefit cost (credit) | ​ | $ | 70 | ​ | $ | (46) | ​ | $ | 210 | ​ | $ | (136)
Schedule of trading gains (losses) related to SERP assets | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Three months ended | ​ | Nine months ended
​ | ​ | September 30, | ​ | September 30,
(in thousands) |  | 2019 |  | 2018 |  | 2019 |  | 2018
Unrealized gains, net | ​ | $ | 370 | ​ | $ | 861 | ​ | $ | 4,006 | ​ | $ | 1,246

X
- Definition Tabular disclosure of selected highly compensated employees to defer a portion of their compensation into the non-qualified Supplemental Retirement Plan ("SERP"). + References No definition available. + Details
Name: | res_TradingGainsLossRelatedToSupplementalRetirementPlanAssetsTableTextBlock
Namespace Prefix: | res_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_CompensationAndRetirementDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfNetBenefitCostsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration