Revenue from Contracts with Customers - Summary of Revenue from Contracts with Customers (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Total revenues	$ 553,046	$ 560,109	$ 1,621,881	$ 1,581,986
Retail [Member]
Disaggregation of Revenue [Line Items]
Total revenues	377,886	366,816	1,158,441	1,112,147
Wholesale Segment [Member]
Disaggregation of Revenue [Line Items]
Total revenues	175,160	193,293	463,440	469,839
Party City Stores [Member] | Retail [Member]
Disaggregation of Revenue [Line Items]
Net sales	336,355	324,766	1,043,422	993,652
Global E-commerce [Member] | Retail [Member]
Disaggregation of Revenue [Line Items]
Net sales	34,221	34,130	102,083	104,314
Temporary Stores [Member] | Retail [Member]
Disaggregation of Revenue [Line Items]
Net sales	5,104	5,161	5,104	5,161
Domestic [Member] | Wholesale Segment [Member]
Disaggregation of Revenue [Line Items]
Net sales	88,287	98,801	247,243	264,496
International [Member] | Wholesale Segment [Member]
Disaggregation of Revenue [Line Items]
Net sales	86,873	94,492	216,197	205,343
Net Sales [Member]
Disaggregation of Revenue [Line Items]
Net sales	550,840	557,350	1,614,049	1,572,966
Net Sales [Member] | Retail [Member]
Disaggregation of Revenue [Line Items]
Net sales	375,680	364,057	1,150,609	1,103,127
Royalties and Franchise Fees [Member]
Disaggregation of Revenue [Line Items]
Net sales	2,206	2,759	7,832	9,020
Royalties and Franchise Fees [Member] | Retail [Member]
Disaggregation of Revenue [Line Items]
Net sales	$ 2,206	$ 2,759	$ 7,832	$ 9,020