Restructuring and other impairment charges - Restructuring program (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	$ 17,103	$ 15,239	$ 60,120
Asset impairment charges	21,388	6,966	19,110
Total restructuring and impairment charges	38,491	22,205	79,230
2020 Workforce reduction plan
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	8,847
2019 Footprint realignment plan
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	1,542	13,753
2018 Footprint realignment plan
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	5,948	(939)	54,993
Other restructuring programs
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	766	2,425	5,127
Termination benefits
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	14,634	12,683	57,812
Asset impairment charges	0	0	0
Total restructuring and impairment charges	14,634	12,683	57,812
Termination benefits | 2020 Workforce reduction plan
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	8,494
Termination benefits | 2019 Footprint realignment plan
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	647	13,683
Termination benefits | 2018 Footprint realignment plan
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	5,565	(1,787)	53,992
Termination benefits | Other restructuring programs
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	(72)	787	3,820
Other costs
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	2,469	2,556	2,308
Asset impairment charges	21,388	6,966	19,110
Total restructuring and impairment charges	23,857	9,522	21,418
Other costs | 2020 Workforce reduction plan
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	353
Other costs | 2019 Footprint realignment plan
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	895	70
Other costs | 2018 Footprint realignment plan
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	383	848	1,001
Other costs | Other restructuring programs
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	$ 838	$ 1,638	$ 1,307