Condensed Consolidated Statement of Stockholders' Equity - 9 months ended Sep. 30, 2018 - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Total Party City Holdco Inc. Stockholders' Equity Before Common Stock Held In Treasury [Member]	Common Stock Held In Treasury [Member]	Total Party City Holdco Inc. Stockholders' Equity [Member]	Non-Controlling Interests [Member]
Balance at Dec. 31, 2017	$ 968,790	$ 1,198	$ 917,192	$ 372,596	$ (35,818)	$ 1,255,168	$ (286,733)	$ 968,435	$ 355
Cumulative effect of change in accounting principle, net (see Note 2)	(78)			(78)		(78)		(78)
Balance, as adjusted at Dec. 31, 2017	968,712	1,198	917,192	372,518	(35,818)	1,255,090	(286,733)	968,357	355
Net income	24,445			24,532		24,532		24,532	(87)
Net income attributable to redeemable securities holder	402			402		402		402
Stock option expense	1,492		1,492			1,492		1,492
Restricted stock units - time-based	722	1	721			722		722
Restricted stock units - performance-based	1,482	5	1,477			1,482		1,482
Director - non-cash compensation	196		196			196		196
Warrant expense	242		242			242		242
Exercise of stock options	878	1	877			878		878
Foreign currency adjustments	(4,909)				(4,888)	(4,888)		(4,888)	(21)
Impact of foreign exchange contracts, net	1,353				1,353	1,353		1,353
Balance at Sep. 30, 2018	$ 995,015	$ 1,205	$ 922,197	$ 397,452	$ (39,353)	$ 1,281,501	$ (286,733)	$ 994,768	$ 247