Debt (Senior notes) (Details) - USD ($)		12 Months Ended
Jun. 29, 2018	Dec. 31, 2018
Debt Instrument [Line Items]
Stated interest rate		5.95%
8.75% Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount	$ 300,000,000
Estimated offering costs	7,337,000
Net proceeds from issuance of debt	$ 292,663,000
Stated interest rate	8.75%
Aggregate principal amount of notes (as a percent)		35.00%
Aggregate principal amount of notes remains outstanding (as a percent)		60.00%
Redemption period		180 days
Aggregate principal amount of outstanding notes (as a percent)		25.00%
Principal amount accrued and unpaid interest (as a percent)		101.00%
8.75% Senior Notes \| Minimum
Debt Instrument [Line Items]
Redemption price, percentage to principal amount		100.00%
8.75% Senior Notes \| Prior to July 15, 2020
Debt Instrument [Line Items]
Redemption price, percentage to principal amount		108.75%

Debt instrument principal amount, accrued and unpaid interest percentage.

No definition available.

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Period Type:	duration

- Definition

Debt instrument redemption aggregate principal amount maximum percentage.

+ References

No definition available.

+ Details

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- Definition

Debt Instrument, Redemption Period, After Equity Offering Closing

+ References

No definition available.

+ Details

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- Definition

Debt instrument, redemption price, percentage of aggregate principal amount of notes remains outstanding.

+ References

No definition available.

+ Details

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- Definition

Estimated offering costs of debt.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Minimum percentage of principal holders required to declare outstanding amounts due.

+ References

No definition available.

+ Details

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Namespace Prefix:	chpe_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

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Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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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

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- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585

+ Details

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- Details

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