Income taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Contingency [Line Items]
Cumulative unremitted earnings, non-permanently reinvested	$ 1,700,000
Cumulative unremitted earnings, permanently reinvested	$ 700,000
Effective income tax rate, total	6.10%	(35.90%)	10.60%
Increase (decrease) in deferred tax liability due to merger of foreign subsidiaries	$ (129,000)
Realized net benefit as result of reducing our reserves with respect to uncertain tax positions	1,700	$ 100	$ 800
Tax effect, carry forwards	180,800
Deferred tax assets, valuation allowance	155,008	119,233
Unrecognized tax benefits that would impact effective tax rate	4,400
Unrecognized tax benefits, interest (benefit) expense	200	200	200
Unrecognized tax benefits, penalties	(500)	(100)	$ (300)
Unrecognized tax benefits, interest (benefit) expense accrued	600	600
Unrecognized tax benefits, penalties accrued	2,100	$ 2,200
Minimum
Income Tax Contingency [Line Items]
Unrecognized tax benefits change within next twelve months due to potential for resolution of foreign and U.S. examinations	0
Maximum
Income Tax Contingency [Line Items]
Unrecognized tax benefits change within next twelve months due to potential for resolution of foreign and U.S. examinations	700
No Expiration Date
Income Tax Contingency [Line Items]
Tax effect, carry forwards	14,400
After 2020 but before the end of 2025
Income Tax Contingency [Line Items]
Tax effect, carry forwards	9,100
After 2025
Income Tax Contingency [Line Items]
Tax effect, carry forwards	$ 157,300