Schedule I - Condensed Financial Information of Registrant - Condensed Statements of Cash Flows (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows provided by (used in) operating activities:
Net income	$ (268,829)	$ (281,745)	$ 48,005	$ (30,289)	$ 98,374	$ (2,440)	$ 28,048	$ (1,163)	$ (532,858)	$ 122,819	$ 215,340
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Change in due to/from affiliates									(65,617)	12,138	19,408
Net cash (used in) provided by operating activities									43,693	101,856	267,883
Cash flows (used in) provided by financing activities:
Treasury stock purchases									(156)	(40,197)	(286,733)
Exercise of stock options									1,148	2,269	1,298
Net cash (used in) provided by financing activities									(237,710)	56,170	(139,962)
Party City Holdco Inc. [Member]
Cash flows provided by (used in) operating activities:
Net income									(532,495)	122,850	215,340
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Equity in net income of subsidiaries									532,495	(122,850)	(215,340)
Change in due to/from affiliates									(989)	37,928	285,435
Net cash (used in) provided by operating activities									(989)	37,928	285,435
Cash flows (used in) provided by financing activities:
Treasury stock purchases									(156)	(40,197)	(286,733)
Exercise of stock options									1,145	2,269	1,298
Net cash (used in) provided by financing activities									989	$ (37,928)	$ (285,435)
Net change in cash and cash equivalents									$ 0