Debt instrument additional basis spread.

No definition available.

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

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 3: 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))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Description of the frequency of periodic payments (monthly, quarterly, annual).

+ 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)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

+ Details

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

- Definition

Description of the interest rate as being fixed or variable, and, if variable, identification of the index or rate on which the interest rate is based and the number of points or percentage added to that index or rate to set the rate, and other pertinent information, such as frequency of rate resets.

+ References

+ Details

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

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Specific incremental costs directly attributable to a proposed or actual offering of securities which are deferred at the end of the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.A)
-URI http://asc.fasb.org/extlink&oid=27011391&loc=d3e105025-122735

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.8)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DeferredOfferingCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Description of the frequency of periodic payments, which may be presented in a variety of ways (for example, monthly, quarterly, annually).

+ References

+ Details

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

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

- Definition

Amount of the required periodic payment applied to principal.

+ References

+ Details

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

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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

- Definition

The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time.

+ References

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

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- Details

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Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=ichr_CreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=ichr_FederalFundRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Balance Type:
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- Details

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- Details

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- Details

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Namespace Prefix:
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Long-Term Debt - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended
	Feb. 15, 2018	Mar. 27, 2020	Dec. 27, 2019
Line Of Credit Facility [Line Items]
Total principal amount of long-term debt		$ 183,849	$ 181,037
Term Loan
Line Of Credit Facility [Line Items]
Total principal amount of long-term debt		159,687	161,875
Revolving Credit Facility
Line Of Credit Facility [Line Items]
Total principal amount of long-term debt		$ 24,162	$ 19,162
Credit Agreement
Line Of Credit Facility [Line Items]
Debt issuance costs	$ 2,100
Description of interest rate		The Base Rate is equal to the higher of i) the Prime Rate, ii) the Federal Funds Rate plus 0.5%, or iii) the Eurodollar Rate plus 1.00%. The Eurodollar rate is equal to LIBOR. The applicable margin on Base Rate and Eurodollar Rate loans is 0.751.50% and 1.752.50% per annum, respectively, depending on our leverage ratio.
Credit Agreement \| Federal Funds Effective Rate
Line Of Credit Facility [Line Items]
Basis spread on variable rate	0.50%
Credit Agreement \| Eurodollar Rate
Line Of Credit Facility [Line Items]
Basis spread on variable rate	1.00%
Frequency of interest payment		Last day of the applicable interest period
Credit Agreement \| Eurodollar Rate \| Minimum
Line Of Credit Facility [Line Items]
Additional basis spread on variable rate	1.75%
Credit Agreement \| Eurodollar Rate \| Maximum
Line Of Credit Facility [Line Items]
Additional basis spread on variable rate	2.50%
Credit Agreement \| Base Rate
Line Of Credit Facility [Line Items]
Frequency of interest payment		Quarterly
Credit Agreement \| Base Rate \| Minimum
Line Of Credit Facility [Line Items]
Additional basis spread on variable rate	0.75%
Credit Agreement \| Base Rate \| Maximum
Line Of Credit Facility [Line Items]
Additional basis spread on variable rate	1.50%
Credit Agreement \| Term Loan
Line Of Credit Facility [Line Items]
Total principal amount of long-term debt	$ 175,000
Credit facility, periodic principal payments		$ 2,200
Principal payments maturity date		Feb. 15, 2023
Credit facility, frequency of principal payments		quarterly
Credit Agreement \| Term Loan \| Eurodollar Rate
Line Of Credit Facility [Line Items]
Interest rate		4.44%
Credit Agreement \| Revolving Credit Facility
Line Of Credit Facility [Line Items]
Total principal amount of long-term debt	$ 125,000
Principal payments maturity date		Feb. 15, 2023
Credit Agreement \| Revolving Credit Facility \| Minimum
Line Of Credit Facility [Line Items]
Percentage of commitment fee on unused portion of revolver	0.20%
Credit Agreement \| Revolving Credit Facility \| Maximum
Line Of Credit Facility [Line Items]
Percentage of commitment fee on unused portion of revolver	0.35%
Credit Agreement \| Revolving Credit Facility \| Eurodollar Rate
Line Of Credit Facility [Line Items]
Interest rate		4.19%