ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) (Reclassifications From Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Amount Reclassified from Accumulated Other Comprehensive Income
Interest expense									$ (33,244)	$ (35,489)	$ (32,626)
Miscellaneous, net									(4,614)	1,556	5,550
Income before Income Taxes									301,155	342,069	266,020
Tax benefit									(87,065)	(99,842)	(71,254)
Net income attributable to AptarGroup, Inc.	$ 53,232	$ 63,716	$ 41,839	$ 55,253	$ 48,533	$ 56,750	$ 73,915	$ 63,004	214,040	242,202	194,745
Amount Reclassified from Accumulated Other Comprehensive Income
Amount Reclassified from Accumulated Other Comprehensive Income
Net income attributable to AptarGroup, Inc.									15,701	(5,190)	(9,536)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent | Amount Reclassified from Accumulated Other Comprehensive Income
Amount Reclassified from Accumulated Other Comprehensive Income
Income before Income Taxes									8,203	3,850	7,309
Tax benefit									(1,989)	(977)	(1,785)
Net income attributable to AptarGroup, Inc.									6,214	2,873	5,524
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent | Amount Reclassified from Accumulated Other Comprehensive Income
Amount Reclassified from Accumulated Other Comprehensive Income
Total Net periodic benefit cost									7,805	3,401	6,589
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent | Amount Reclassified from Accumulated Other Comprehensive Income
Amount Reclassified from Accumulated Other Comprehensive Income
Total Net periodic benefit cost									(398)	(449)	(720)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent | Amount Reclassified from Accumulated Other Comprehensive Income
Amount Reclassified from Accumulated Other Comprehensive Income
Income before Income Taxes									9,487	(8,063)	(18,149)
Tax benefit									0	0	3,089
Net income attributable to AptarGroup, Inc.									9,487	(8,063)	(15,060)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent | Changes in treasury locks | Amount Reclassified from Accumulated Other Comprehensive Income
Amount Reclassified from Accumulated Other Comprehensive Income
Interest expense									0	0	26
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent | Changes in cross currency swap: interest component | Amount Reclassified from Accumulated Other Comprehensive Income
Amount Reclassified from Accumulated Other Comprehensive Income
Interest expense									(1,474)	(4,805)	(5,150)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent | Changes in cross currency swap: foreign exchange component | Amount Reclassified from Accumulated Other Comprehensive Income
Amount Reclassified from Accumulated Other Comprehensive Income
Miscellaneous, net									$ 10,961	$ (3,258)	$ (13,025)