Common stock issued in exchange.

No definition available.

Name:	prty_CommonStockIssuedInExchange
Namespace Prefix:	prty_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Debt instrument face amount of notes exchanged.

+ References

No definition available.

+ Details

Name:	prty_DebtInstrumentFaceAmountOfNotesExchanged
Namespace Prefix:	prty_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt instrument floor basic points.

+ References

No definition available.

+ Details

Name:	prty_DebtInstrumentFloorBasicPoints
Namespace Prefix:	prty_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument interest rate during period payable in cash.

+ References

No definition available.

+ Details

Name:	prty_DebtInstrumentInterestRateDuringPeriodPayableInCash
Namespace Prefix:	prty_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument interest rate during period payable on incremental principal.

+ References

No definition available.

+ Details

Name:	prty_DebtInstrumentInterestRateDuringPeriodPayableOnIncrementalPrincipal
Namespace Prefix:	prty_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument maturity period.

+ References

No definition available.

+ Details

Name:	prty_DebtInstrumentMaturityPeriod
Namespace Prefix:	prty_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument offered rate plus basis point.

+ References

No definition available.

+ Details

Name:	prty_DebtInstrumentOfferedRatePlusBasisPoint
Namespace Prefix:	prty_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument principal balance of notes not participants in exchange.

+ References

No definition available.

+ Details

Name:	prty_DebtInstrumentPrincipalBalanceOfNotesNotParticipantsInExchange
Namespace Prefix:	prty_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt instrument principal balance of notes not participants in exchange net.

+ References

No definition available.

+ Details

Name:	prty_DebtInstrumentPrincipalBalanceOfNotesNotParticipantsInExchangeNet
Namespace Prefix:	prty_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt instrument undiscounted value including interest expense.

+ References

No definition available.

+ Details

Name:	prty_DebtInstrumentUndiscountedValueIncludingInterestExpense
Namespace Prefix:	prty_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Proceeds from stock exchange.

+ References

No definition available.

+ Details

Name:	prty_ProceedsFromStockExchange
Namespace Prefix:	prty_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Restructured debt carrying amount.

+ References

No definition available.

+ Details

Name:	prty_RestructuredDebtCarryingAmount
Namespace Prefix:	prty_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Troubled debt restructuring third-party fees.

+ References

No definition available.

+ Details

Name:	prty_TroubledDebtRestructuringThirdPartyFees
Namespace Prefix:	prty_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Face amount or stated value per share of common stock.

+ References

+ Details

Name:	us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentDescriptionOfVariableRateBasis
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
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=119993939&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

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
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

+ Details

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

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6036836-161870

Reference 2: 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=119993939&loc=d3e28551-108399

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(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateEffectivePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

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

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
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_DebtInstrumentLineItems
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=120391452&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

For a debtor, the aggregate gain (loss) recognized on the restructuring of payables arises from the difference between the book value of the debt before the restructuring and the fair value of the payments on the debt after restructuring is complete.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 60
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6402221&loc=d3e15743-112638

+ Details

Name:	us-gaap_GainsLossesOnRestructuringOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Number of new stock issued during the period.

+ 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(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 4: 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(28))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_TypeOfArrangementAxis=prty_RefinancingTransactionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=prty_SixPointOneTwoFivePercentageSeniorNotesDue2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=prty_SixPointSixTwoFivePercentageSeniorNotesDue2026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=prty_SeniorSecuredFirstLienFloatingRateNotesDueTwoThousandTwentyFiveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=prty_TenPointZeroZeroPercentagePaymentInKindCashSeniorSecuredSecondLienNotesDueTwoThousandTwentySixMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=prty_FifteenPointZeroZeroPercentagePaymentInKindCashSeniorSecuredFirstLienNotesDueTwoThousandTwentyFiveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=prty_FirstLienPartyCityNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=prty_FirstLienPartyCityNotesMatureOnJulyFifteenTwoThousandTwentyFiveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_LongtermDebtTypeAxis=prty_FirstLienPartyAnagramNotesMatureOnAugustFifteenTwoThousandTwentyFiveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=prty_SecondLienPartyAnagramNotesMatureOnAugustFifteenTwoThousandTwentySixMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Long-Term Obligations - First Lien Party City Notes, First Lien Anagram Notes, Second Lien Anagram Notes - Additional Information (Detail) $ / shares in Units, $ in Thousands		12 Months Ended
	Jul. 30, 2020 USD ($) BasisPoint $ / shares shares	Dec. 31, 2020 USD ($) $ / shares	Dec. 31, 2019
Debt Instrument [Line Items]
Aggregate principal amount		$ 1,194,737
Common stock, par value \| $ / shares		$ 0.01
Refinancing Transactions [Member]
Debt Instrument [Line Items]
Common stock issued \| shares	15,942,551
Common stock, par value \| $ / shares	$ 0.01
6.125% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Aggregate principal amount		$ 22,924
Notes issued rate		6.125%	6.125%
Debt instrument maturity period		2023	2023
6.125% Senior Notes due 2023 [Member] \| Refinancing Transactions [Member]
Debt Instrument [Line Items]
Aggregate principal amount	$ 327,076
Notes issued rate	6.125%
Debt instrument maturity period	2023
6.625% Senior Notes due 2026 [Member]
Debt Instrument [Line Items]
Aggregate principal amount		$ 107,254
Notes issued rate		6.625%	6.625%
Debt instrument maturity period		2026	2026
6.625% Senior Notes due 2026 [Member] \| Refinancing Transactions [Member]
Debt Instrument [Line Items]
Aggregate principal amount	$ 392,746
Notes issued rate	6.625%
Debt instrument maturity period	2026
Senior Secured First Lien Floating Rate Notes Due Two Thousand Twenty Five \| Refinancing Transactions [Member]
Debt Instrument [Line Items]
Aggregate principal amount	$ 156,669
Debt instrument maturity period	2025
10.00% PIK/Cash Senior Secured Second Lien Notes due 2026 [Member] \| Refinancing Transactions [Member]
Debt Instrument [Line Items]
Aggregate principal amount	$ 84,687
Notes issued rate	10.00%
Debt instrument maturity period	2026
15.00% PIK/Cash Senior Secured First Lien Notes due 2025 [Member] \| Refinancing Transactions [Member]
Debt Instrument [Line Items]
Aggregate principal amount	$ 110,000
Notes issued rate	15.00%
Debt instrument maturity period	2025
First Lien Party City Notes \| Refinancing Transactions [Member]
Debt Instrument [Line Items]
Aggregate principal amount	$ 5,000
First Lien Party City Notes [Member]
Debt Instrument [Line Items]
Aggregate principal amount		$ 161,669
First Lien Party City Notes [Member] \| Refinancing Transactions [Member]
Debt Instrument [Line Items]
Aggregate principal amount	$ 161,669
Debt instrument maturity date	Jul. 15, 2025
First Lien Party City Notes [Member] \| Refinancing Transactions [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument, description of variable rate basis	Interest on the First Lien Party City Notes accrues from the Settlement Date at a floating rate equal to the 6-month London Inter-Bank Offered Rate plus 500 basis points (with a floor of 75 basis points) per annum, payable semi-annually in arrears on January 15 and July 15 of each year, commencing January 15, 2021.
Debt instrument, offered rate plus basis points \| BasisPoint	500
Debt instrument, floor basis points \| BasisPoint	75
Debt instrument, frequency of periodic payment	semi-annually
First Lien Anagram Notes [Member]
Debt Instrument [Line Items]
Aggregate principal amount		110,000
Gain on restructuring of debt		273,149
Third-party fees incurred		18,902
Common stock issued in exchange		27,007
Cash received from participants in the exchange		39,544
Debt instrument, principal amount notes exchanged		44,500
Debt instrument undiscounted value including interest expense		82,160
Carrying amount of restructured debt		$ 32,328
Effective interest rate		3.50%
Principal balance of notes not participants in exchange		$ 50,500
Principal balance of notes after netting		45,678
First Lien Anagram Notes [Member] \| Refinancing Transactions [Member]
Debt Instrument [Line Items]
Aggregate principal amount	$ 110,000
Debt instrument maturity date	Aug. 15, 2025
Debt instrument, description of variable rate basis	Interest on the First Lien Anagram Notes accrues from the Settlement Date at (i) a rate of 10.00% per annum, payable in cash; and (ii) a rate of 5.00% per annum payable by increasing the principal amount of the outstanding First Lien Anagram Notes or issuing additional First Lien Anagram Notes, as the case may be, in each case payable semi-annually in arrears on February 15 and August 15 of each year, commencing February 15, 2021.
Debt instrument, frequency of periodic payment	semi-annually
Debt instrument, interest rate payable in cash	10.00%
Debt instrument, interest rate payable on incremental principal	5.00%
Second Lien Anagram Notes [Member]
Debt Instrument [Line Items]
Aggregate principal amount		$ 84,687
Second Lien Anagram Notes [Member] \| Refinancing Transactions [Member]
Debt Instrument [Line Items]
Aggregate principal amount	$ 84,687
Debt instrument maturity date	Aug. 15, 2026
Debt instrument, description of variable rate basis	Interest on the Second Lien Anagram Notes accrues from the Settlement Date at (i) a rate of 5.00% per annum, payable, at the Anagram Issuers’ option, entirely in cash or entirely by increasing the principal amount of the outstanding Second Lien Anagram Notes or issuing additional Second Lien Anagram Notes, as the case may be; and (ii) a rate of 5.00% per annum payable by increasing the principal amount of the outstanding Second Lien Anagram Notes or issuing additional Second Lien Anagram Notes, as the case may be, in each case payable semi-annually in arrears on February 15 and August 15 of each year, commencing February 15, 2021
Debt instrument, frequency of periodic payment	semi-annually
Debt instrument, interest rate payable in cash	5.00%
Debt instrument, interest rate payable on incremental principal	5.00%