Schedule I - Condensed Financial Information of Registrant - Condensed Statements of Operations and Comprehensive Income (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
Condensed Income Statements, Captions [Line Items]
Net income	$ (268,829)	$ (281,745)	$ 48,005	$ (30,289)	$ 98,374	$ (2,440)	$ 28,048	$ (1,163)	$ (532,858)	$ 122,819	$ 215,340
Add: Net income attributable to redeemable securities holder										(409)
Net (loss) income attributable to common shareholders of Party City Holdco Inc	$ (268,818)	$ (281,533)	$ 48,074	$ (30,218)	$ 98,325	$ (2,420)	$ 28,487	$ (1,133)	(532,495)	123,259	215,340
Other comprehensive (loss) income, net									13,444	(13,416)	16,421
Comprehensive (loss) income									(519,414)	109,403	231,761
Comprehensive income attributable to redeemable securities holder										409
Comprehensive (loss) income attributable to common shareholders of Party City Holdco Inc.									(519,028)	109,876	231,761
Party City Holdco Inc. [Member]
Condensed Income Statements, Captions [Line Items]
Equity in net income of subsidiaries									(532,495)	122,850	215,340
Net income									(532,495)	122,850	215,340
Add: Net income attributable to redeemable securities holder										409
Net (loss) income attributable to common shareholders of Party City Holdco Inc									(532,495)	123,259	215,340
Other comprehensive (loss) income, net									13,467	(13,383)	16,421
Comprehensive (loss) income									(519,028)	109,467	231,761
Comprehensive income attributable to redeemable securities holder										409
Comprehensive (loss) income attributable to common shareholders of Party City Holdco Inc.									$ (519,028)	$ 109,876	$ 231,761