Revenue from Contracts with Customers - Summary of Revenue from Contracts with Customers (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenues	$ 1,850,690	$ 2,348,789	$ 2,427,515
Retail Segment [Member]
Disaggregation of Revenue [Line Items]
Total revenues	1,382,325	1,751,415	1,813,907
Wholesale Segment [Member]
Disaggregation of Revenue [Line Items]
Total revenues	468,365	597,374	613,608
Party City Stores [Member] | Retail Segment [Member]
Disaggregation of Revenue [Line Items]
Net sales	1,367,434	1,529,043	1,583,134
Global E-commerce [Member] | Retail Segment [Member]
Disaggregation of Revenue [Line Items]
Net sales		162,490	154,481
Temporary Stores [Member] | Retail Segment [Member]
Disaggregation of Revenue [Line Items]
Net sales	7,645	50,603	65,219
Net Sales [Member]
Disaggregation of Revenue [Line Items]
Net sales	1,843,444	2,339,510	2,416,442
Net Sales [Member] | Retail Segment [Member]
Disaggregation of Revenue [Line Items]
Net sales	1,375,079	1,742,136	1,802,834
Royalties and Franchise Fees [Member]
Disaggregation of Revenue [Line Items]
Net sales	7,246	9,279	11,073
Royalties and Franchise Fees [Member] | Retail Segment [Member]
Disaggregation of Revenue [Line Items]
Net sales	7,246	9,279	11,073
Domestic | Wholesale Segment [Member]
Disaggregation of Revenue [Line Items]
Net sales	238,936	310,042	328,056
International [Member] | Wholesale Segment [Member]
Disaggregation of Revenue [Line Items]
Net sales	$ 229,429	$ 287,332	$ 285,552