- Definition

Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

Name:	invest_DerivativeNonmonetaryNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

The average cap rate on a group of price risk derivatives such as caps or collars. A payment or receipt is triggered if the market rate exceeds the cap rate on the contract.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeAverageCapPrice
Namespace Prefix:	us-gaap_
Data Type:	us-types:perUnitItemType
Balance Type:	na
Period Type:	instant

- Definition

The average floor rate on a group of price risk derivatives such as floors or collars. A payment or receipt is triggered if the market rate falls below the floor rate on the contract.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeAverageFloorPrice
Namespace Prefix:	us-gaap_
Data Type:	us-types:perUnitItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Average fixed price related to the group of price risk swap derivatives.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeSwapTypeAverageFixedPrice
Namespace Prefix:	us-gaap_
Data Type:	us-types:perUnitItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_SwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=chpe_DerivativeMaturingInTwoThousandEighteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=chpe_CrudeOilDerivativeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=chpe_NaturalGasDerivativeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=chpe_DerivativeMaturingInTwoThousandNineteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=chpe_DerivativeMaturingInTwoThousandTwentyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=chpe_CostlessCollarMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Derivative instruments - Summary of derivatives outstanding (Details) bbl in Thousands, MMBTU in Thousands	Feb. 28, 2018 $ / bbl	Dec. 31, 2017 bbl MMBTU $ / bbl $ / MMBTU
Swaps \| Derivative Maturing in 2018
Derivative [Line Items]
Weighted average fixed price	54.80
Swaps \| Derivative Maturing in 2018 \| Crude Oil Derivative Contracts
Derivative [Line Items]
Volume \| bbl		2,116
Weighted average fixed price		54.92
Swaps \| Derivative Maturing in 2018 \| Natural Gas Derivative Contracts
Derivative [Line Items]
Volume \| MMBTU		10,491
Weighted average fixed price \| $ / MMBTU		2.87
Swaps \| Derivative Maturing in 2019 \| Crude Oil Derivative Contracts
Derivative [Line Items]
Volume \| bbl		1,312
Weighted average fixed price		54.26
Swaps \| Derivative Maturing in 2019 \| Natural Gas Derivative Contracts
Derivative [Line Items]
Volume \| MMBTU		7,632
Weighted average fixed price \| $ / MMBTU		2.81
Swaps \| Derivative Maturing in 2020
Derivative [Line Items]
Weighted average fixed price	46.26
Swaps \| Derivative Maturing in 2020 \| Crude Oil Derivative Contracts
Derivative [Line Items]
Volume \| bbl		1,004
Weighted average fixed price		51.32
Swaps \| Derivative Maturing in 2020 \| Natural Gas Derivative Contracts
Derivative [Line Items]
Volume \| MMBTU		3,600
Weighted average fixed price \| $ / MMBTU		2.77
Collars \| Derivative Maturing in 2018 \| Crude Oil Derivative Contracts
Derivative [Line Items]
Volume \| bbl		183
Weighted average fixed price per Bbl, purchased puts		50.00
Weighted average fixed price per Bbl, sold calls		60.50