Long-Term Obligations - Summary of Long-Term Obligations (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Total long-term obligations, Principal Amount	$ 1,194,737
Total long-term obligations, Gross Carrying Amount	1,349,489
Total long term obligations, Deferred Financing Costs	6,105
Total long-term obligations, Net Carrying Amount	1,343,384	$ 1,575,511
Current portion, Net Carrying Amount	(13,576)	(71,524)
Long-term obligations excluding current portion, Principal Amount	1,181,161
Long-term obligations excluding current portion, Gross Carrying Amount	1,335,913
Long-term obligations excluding current portion, Deferred Financing	(6,105)
Long-term obligations excluding current portion, Net Carrying Amount	1,329,808	1,503,987
Senior Secured Term Loan Facility [Member] | Term Loan Credit Agreement [Member]
Debt Instrument [Line Items]
Total long-term obligations, Principal Amount	694,220
Total long-term obligations, Gross Carrying Amount	694,220
Total long term obligations, Deferred Financing Costs	4,055
Total long-term obligations, Net Carrying Amount	690,165	718,596
6.125% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Total long-term obligations, Principal Amount	22,924
Total long-term obligations, Gross Carrying Amount	22,924
Total long term obligations, Deferred Financing Costs	145
Total long-term obligations, Net Carrying Amount	22,779	347,015
6.625% Senior Notes due 2026 [Member]
Debt Instrument [Line Items]
Total long-term obligations, Principal Amount	107,254
Total long-term obligations, Gross Carrying Amount	107,254
Total long term obligations, Deferred Financing Costs	939
Total long-term obligations, Net Carrying Amount	106,315	494,910
First Lien Party City Notes [Member]
Debt Instrument [Line Items]
Total long-term obligations, Principal Amount	161,669
Total long-term obligations, Gross Carrying Amount	206,775
Total long-term obligations, Net Carrying Amount	206,775
First Lien Anagram Notes [Member]
Debt Instrument [Line Items]
Total long-term obligations, Principal Amount	110,000
Total long-term obligations, Gross Carrying Amount	152,301
Total long term obligations, Deferred Financing Costs	966
Total long-term obligations, Net Carrying Amount	151,335
Second Lien Anagram Notes [Member]
Debt Instrument [Line Items]
Total long-term obligations, Principal Amount	84,687
Total long-term obligations, Gross Carrying Amount	152,032
Total long-term obligations, Net Carrying Amount	152,032
Finance lease obligations [Member]
Debt Instrument [Line Items]
Total long-term obligations, Principal Amount	13,983
Total long-term obligations, Gross Carrying Amount	13,983
Total long-term obligations, Net Carrying Amount	$ 13,983	$ 14,990