Selling, general and administrative expenses (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Selling, General and Administrative Expense [Abstract]
Personnel expenses	$ 104,765	$ 122,453	$ 132,694
Share-based compensation	69,187	69,410	95,176
Professional services	24,480	24,287	24,264
Travel expenses	7,809	17,604	21,790
Office expenses	12,974	14,095	14,784
Other expenses	22,946	19,609	16,518
Total selling, general and administrative expenses	$ 242,161	$ 267,458	$ 305,226

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of expense for salary, wage, profit sharing; incentive and equity-based compensation; and other employee benefit.

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Amount of general expenses not normally included in Other Operating Costs and Expenses.

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Amount of selling, general and administrative expense classified as other.

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A fee charged for services from professionals such as doctors, lawyers and accountants. The term is often expanded to include other professions, for example, pharmacists charging to maintain a medicinal profile of a client or customer.

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The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.

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Expenses incurred for travel and entertainment during the period.

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