Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Cumulative Effect of Change in Accounting Principle, Net [Member]	Cumulative Effect of Change in Accounting Principle, Net Adjusted [Member]	Time-Based Units [Member]	Performance-Based Units [Member]	Common Stock [Member]	Common Stock [Member] Cumulative Effect of Change in Accounting Principle, Net Adjusted [Member]	Common Stock [Member] Time-Based Units [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] Cumulative Effect of Change in Accounting Principle, Net [Member]	Additional Paid-in Capital [Member] Cumulative Effect of Change in Accounting Principle, Net Adjusted [Member]	Additional Paid-in Capital [Member] Time-Based Units [Member]	Additional Paid-in Capital [Member] Performance-Based Units [Member]	Retained Earnings (Deficit) [Member]	Retained Earnings (Deficit) [Member] Cumulative Effect of Change in Accounting Principle, Net [Member]	Retained Earnings (Deficit) [Member] Cumulative Effect of Change in Accounting Principle, Net Adjusted [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Other Comprehensive Loss [Member] Cumulative Effect of Change in Accounting Principle, Net Adjusted [Member]	Total Party City Holdco Inc. Stockholders' Equity Before Common Stock Held In Treasury [Member]	Total Party City Holdco Inc. Stockholders' Equity Before Common Stock Held In Treasury [Member] Cumulative Effect of Change in Accounting Principle, Net [Member]	Total Party City Holdco Inc. Stockholders' Equity Before Common Stock Held In Treasury [Member] Cumulative Effect of Change in Accounting Principle, Net Adjusted [Member]	Total Party City Holdco Inc. Stockholders' Equity Before Common Stock Held In Treasury [Member] Time-Based Units [Member]	Total Party City Holdco Inc. Stockholders' Equity Before Common Stock Held In Treasury [Member] Performance-Based Units [Member]	Common Stock Held In Treasury [Member]	Common Stock Held In Treasury [Member] Cumulative Effect of Change in Accounting Principle, Net Adjusted [Member]	Total Party City Holdco Inc. Stockholders' Equity [Member]	Total Party City Holdco Inc. Stockholders' Equity [Member] Cumulative Effect of Change in Accounting Principle, Net [Member]	Total Party City Holdco Inc. Stockholders' Equity [Member] Cumulative Effect of Change in Accounting Principle, Net Adjusted [Member]	Total Party City Holdco Inc. Stockholders' Equity [Member] Time-Based Units [Member]	Total Party City Holdco Inc. Stockholders' Equity [Member] Performance-Based Units [Member]	Non-Controlling Interests [Member]	Non-Controlling Interests [Member] Cumulative Effect of Change in Accounting Principle, Net Adjusted [Member]
Balance at Dec. 31, 2017	$ 968,790	$ (78)	$ 968,712			$ 1,198	$ 1,198		$ 917,192		$ 917,192			$ 372,596	$ (78)	$ 372,518	$ (35,818)	$ (35,818)	$ 1,255,168	$ (78)	$ 1,255,090			$ (286,733)	$ (286,733)	$ 968,435	$ (78)	$ 968,357			$ 355	$ 355
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201807Member
Net income (loss)	$ 122,819													122,850					122,850							122,850					(31)
Add: Net income attributable to redeemable securities holder	409													409					409							409
Stock option expense	1,744								1,744										1,744							1,744
Restricted stock units				$ 1,174				$ 6				$ 1,168										$ 1,174							$ 1,174
Directors — non-cash compensation	196								196										196							196
Warrant	(89)								(89)										(89)							(89)
Exercise of stock options	2,269					4			2,265										2,269							2,269
Foreign currency adjustments	(14,479)																(14,446)		(14,446)							(14,446)					(33)
Treasury stock purchases	(40,197)																							(40,197)		(40,197)
Impact of foreign exchange contracts	1,063																1,063		1,063							1,063
Balance at Dec. 31, 2018	$ 1,043,621	$ 159	$ 1,043,780			1,208	$ 1,208		922,476	$ 662	$ 923,138			495,777	$ (503)	$ 495,274	(49,201)	$ (49,201)	1,370,260	$ 159	$ 1,370,419			(326,930)	$ (326,930)	1,043,330	$ 159	$ 1,043,489			291	$ 291
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201807Member
Net income (loss)	$ (532,858)													(532,495)					(532,495)							(532,495)					(363)
Stock option expense	1,319								1,319										1,319							1,319
Restricted stock units				2,033								2,033										2,033							2,033
Directors — non-cash compensation	313								313										313							313
Warrant	515								515										515							515
Exercise of stock options	1,148					3			1,145										1,148							1,148
Foreign currency adjustments	12,599																12,622		12,622							12,622					(23)
Treasury stock purchases	(156)																							(156)		(156)
Acquired non-controlling interest	181								110										110							110					71
Impact of foreign exchange contracts	847													2			845		847							847
Balance at Dec. 31, 2019	529,721					1,211			928,573					(37,219)			(35,734)		856,831					(327,086)		529,745					(24)
Net income (loss)	(528,457)													(528,238)					(528,238)							(528,238)					(219)
Stock option expense				796	$ 7,847							796	$ 7,847									796	$ 7,847						796	$ 7,847
Restricted stock units				$ 2,071	$ 1,272							$ 2,071	$ 1,272									$ 2,071	$ 1,272						$ 2,071	$ 1,272
Directors — non-cash compensation	337								337										337							337
Warrant	1,033								1,033										1,033							1,033
Exercise of stock options	148					2			146										148							148
Issuance of Stock for Debt exchange including costs	27,741					160			27,581										27,741							27,741
Foreign currency adjustments	6,143																6,170		6,170							6,170					(27)
Treasury stock purchases	(96)																							(96)		(96)
Acquired non-controlling interest	2,317								2,316										2,316							2,316					1
Impact of foreign exchange contracts	(352)																(352)		(352)							(352)
Balance at Dec. 31, 2020	$ 50,521					$ 1,373			$ 971,972					$ (565,457)			$ (29,916)		$ 377,972					$ (327,182)		$ 50,790					$ (269)