Acquisitions and dispositions - Acquisitions, Narrative (Details) $ in Thousands								1 Months Ended	12 Months Ended
	Dec. 31, 2019 USD ($) employee	Aug. 09, 2019 USD ($)	Oct. 01, 2018 USD ($) employee facility country	Sep. 30, 2018 USD ($)	Apr. 12, 2018 USD ($) installment	Jul. 24, 2017 USD ($)	Mar. 14, 2017 USD ($) facility	Feb. 28, 2019 USD ($)	Dec. 31, 2019 USD ($) employee acquisition	Dec. 31, 2018 USD ($) acquisition	Dec. 31, 2017 USD ($) acquisition	Sep. 29, 2019 USD ($)
Business Acquisition [Line Items]
Cash paid for acquisition									$ 298,380	$ 277,177	$ 383,725
Payment for contingent consideration liability									5,500	0	0
Carrying value of equity investments	$ 54,339								54,339	55,516
Loss on remeasurement of previously held interest in acquiree									0	4,784	0
Acquisition-related costs									8,842	14,446	13,790
2019 Acquisitions
Business Acquisition [Line Items]
Cash paid for acquisition									$ 297,926
Number of acquisitions | acquisition									2
2018 Acquisitions
Business Acquisition [Line Items]
Cash paid for acquisition										$ 278,777
Number of acquisitions | acquisition										3
2017 Acquisitions
Business Acquisition [Line Items]
Cash paid for acquisition											$ 383,725
Number of acquisitions | acquisition											2
TEQ
Business Acquisition [Line Items]
Cash paid for acquisition	$ 187,292
Entity number of employees (employee) | employee	500								500
Expected value of goodwill to be tax deductible	$ 58,544								$ 58,544
Corenso
Business Acquisition [Line Items]
Cash paid for acquisition		$ 110,634
Expected value of goodwill to be tax deductible		$ 0
Conitex Sonoco Holding BVI Ltd.
Business Acquisition [Line Items]
Cash paid for acquisition			$ 127,782
Entity number of employees (employee) | employee			1,250
Expected value of goodwill to be tax deductible	2,000								2,000
Percentage of controlling asset acquired (percent)			70.00%
Total consideration			$ 134,847
Consideration transferred, liabilities incurred			$ 7,065
Payment for contingent consideration liability								$ 84
Number of manufacturing facilities (facility) | facility			13
Number of countries entity operates | country			10
Fair value of interest held in acquiree immediately before subsequent acquisition				$ 52,543
Carrying value of equity investments												$ 57,327
Loss on remeasurement of previously held interest in acquiree										$ 4,784
Foreign currency translation losses reclassified out of AOCI										897
Compositub
Business Acquisition [Line Items]
Cash paid for acquisition			$ 9,956
Expected value of goodwill to be tax deductible	1,965								$ 1,965
Payment for contingent consideration liability								$ 371
Fair value adjustment to acquisition-date inventory	50
Highland Packaging Solutions
Business Acquisition [Line Items]
Cash paid for acquisition					$ 141,039
Total consideration					148,539
Contingent purchase liability					$ 7,500
Number of annual installments | installment					2
Fair value adjustment to acquisition-date inventory	$ 0
Clear Lam Packaging, Inc.
Business Acquisition [Line Items]
Cash paid for acquisition						$ 164,951
Cash proceeds from working capital adjustments										$ 1,600
Packaging Holdings, Inc.
Business Acquisition [Line Items]
Cash paid for acquisition							$ 218,774
Number of manufacturing facilities (facility) | facility							5
Packaging Holdings, Inc. | United States
Business Acquisition [Line Items]
Number of manufacturing facilities (facility) | facility							4
Packaging Holdings, Inc. | Mexico
Business Acquisition [Line Items]
Number of manufacturing facilities (facility) | facility							1
Packaging Holding and Clear Lam
Business Acquisition [Line Items]
Fair value adjustment to acquisition-date inventory											$ 5,750
Acquisition-related costs											$ 4,345
Accrued expenses and other | Highland Packaging Solutions
Business Acquisition [Line Items]
Contingent purchase liability					$ 5,000
Other liabilities | Highland Packaging Solutions
Business Acquisition [Line Items]
Contingent purchase liability					$ 2,500
Conitex Sonoco Holding BVI Ltd.
Business Acquisition [Line Items]
Interest held in acquiree before subsequent acquisition (percent)				30.00%
Paper mill operations | Conitex Sonoco Holding BVI Ltd.
Business Acquisition [Line Items]
Number of manufacturing facilities (facility) | facility			4
Cone and tube conversion operations | Conitex Sonoco Holding BVI Ltd.
Business Acquisition [Line Items]
Number of manufacturing facilities (facility) | facility			7
Other production | Conitex Sonoco Holding BVI Ltd.
Business Acquisition [Line Items]
Number of manufacturing facilities (facility) | facility			2