Employee Benefit Plan Offering Period

No definition available.

Name:	pkg_EmployeeBenefitPlanOfferingPeriod
Namespace Prefix:	pkg_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Employee Benefit Plan Participant Age for Distribution Not Subject To Penalty

+ References

No definition available.

+ Details

Name:	pkg_EmployeeBenefitPlanParticipantAgeForDistributionNotSubjectToPenalty
Namespace Prefix:	pkg_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Employee Benefit Plan Participant Catch Up Contribution Age

+ References

No definition available.

+ Details

Name:	pkg_EmployeeBenefitPlanParticipantCatchUpContributionAge
Namespace Prefix:	pkg_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Employee Benefit Plan Participants Reaching Age To Elect Service Withdrawal Vested

+ References

No definition available.

+ Details

Name:	pkg_EmployeeBenefitPlanParticipantsReachingAgeToElectServiceWithdrawalVested
Namespace Prefix:	pkg_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Employee Benefit Plan SalaryDeferralContributions

+ References

No definition available.

+ Details

Name:	pkg_EmployeeBenefitPlanSalaryDeferralContributions
Namespace Prefix:	pkg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Employee Benefit Plan Termination of Employment Age

+ References

No definition available.

+ Details

Name:	pkg_EmployeeBenefitPlanTerminationOfEmploymentAge
Namespace Prefix:	pkg_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Employee Benefit Plan TerminationOfEmploymentPermanentDisability

+ References

No definition available.

+ Details

Name:	pkg_EmployeeBenefitPlanTerminationOfEmploymentPermanentDisability
Namespace Prefix:	pkg_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Indicates (true false) whether description of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) is published and made available.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanDescriptionAvailable
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:booleanItemType
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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-SubTopic 205
-Topic 962
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanDescriptionOfPlanLineItems
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of employer matching contribution on eligible participant contribution to employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanEmployerContributionMatchingPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of plan asset, in forfeited nonvested account, no longer allocated to participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanForfeitedNonvestedAccount
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of decrease in forfeited nonvested account of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) from employer contribution.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 962
-SubTopic 325
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478873/962-325-55-17

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (j)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-04(5)(c))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanForfeitedNonvestedAccountDecreaseForEmployerContribution
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of decrease in net asset available for benefit from total administrative expenses as reported in Form 5500 caption for employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Form 5500 is form provided by Department of the Treasury, Internal Revenue Service (IRS); Department of Labor (DOL), Employee Benefit Security Administration (EBSA); and Pension Benefit Guaranty Corporation (PBGC).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Employee Retirement Income Security Act of 1974
-Number 2520
-Section 103
-Subsection 1
-Paragraph b
-Subparagraph (3)
-Publisher DOL-EBSA

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanForm5500CaptionTotalAdministrativeExpense
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of maximum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow.

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMaximumBorrowingAmount
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage of maximum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow to total participant account balance.

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMaximumBorrowingToTotalAccountPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of minimum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow.

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMinimumBorrowingAmount
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of maximum pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), is permitted to contribute.

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantContributionPretaxMaximumAnnualCompensationAmount
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of maximum pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), is permitted to contribute to total pretax annual compensation.

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantContributionPretaxMaximumAnnualCompensationToTotalCompensationPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Interest rate on participant loan in schedule of asset held for investment of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-05(a)(Schedule I))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Employee Retirement Income Security Act of 1974
-Number 2520
-Section 103
-Subsection 10
-Paragraph b
-Subparagraph (1)(i)(D)
-Publisher DOL-EBSA

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantLoanInterestRate
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=pkg_EBP001Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap-ebp_EmployeeBenefitPlanContributionParticipatingEmployerAxis=pkg_EmployeeBenefitPlanEmployerMatchingContributionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Description of the Plan (Additional Information) (Details) - EBP 001 - USD ($)		12 Months Ended
	Jan. 01, 2025	Dec. 31, 2025	Dec. 31, 2024
EBP, Description of Plan [Line Items]
EBP, Description, Available		true
EBP, Matching and retirement savings contributions and earnings		100.00%
EBP, Non-vested accounts		$ 2,593,000	$ 3,048,000
EBP, Employer contributionse reduced forfeited non-vested accounts		$ 3,733,000
Employee Benefit Plan Offering Period		45 days
EBP, Participant Contribution, Pretax, Maximum Annual Compensation, Amount	$ 34,750
Employee Benefit Plan TerminationOfEmploymentPermanentDisability		65 years
Employee Benefit Plan Participant Age for Distribution Not Subject To Penalty		59 years 6 months
Employee Benefit Plan Participants Reaching Age To Elect Service Withdrawal Vested		55 years
Employee Benefit Plan Termination of Employment Age		72 years
EBP, Participant accounts are charged under administrative expenses		$ 12.5
EBP, Note Receivable from participants, account, maximum orrowing, to total account, percentage		50.00%
EBP, Note receivable from participant, account, maximum borrowing, amount		$ 50,000
EBP, Note receivable from participant, account, minimum borrowing, amount		$ 1,000
Employee Benefit Plan, Employer Matching Contribution [Member]
EBP, Description of Plan [Line Items]
EBP, Matching and retirement savings contributions and earnings		100.00%
Maximum
EBP, Description of Plan [Line Items]
Employee Benefit Plan SalaryDeferralContributions		$ 31,000
Employee Benefit Plan Participant Catch Up Contribution Age		50 years
EBP, Participant Contribution, Pretax, Maximum Annual Compensation to Total Compensation, Percentage		10.00%
EBP, Participant Contribution, Pretax, Maximum Annual Compensation, Amount	$ 31,000
Participant interest rate		9.25%
Minimum
EBP, Description of Plan [Line Items]
Employee Benefit Plan SalaryDeferralContributions		$ 23,500
Employee Benefit Plan Participant Catch Up Contribution Age		50 years
EBP, Matching and retirement savings contributions and earnings		6.50%
Participant interest rate		3.25%