Restructuring charges - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
	Apr. 14, 2020	Jun. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 8,548	$ 1,226	$ 25,396
Operating Lease, Impairment Loss			0	0	$ 12,460
Second quarter 2020 restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Expected percent of positions eliminated	20.00%
Restructuring charges				31,500
Second quarter 2020 restructuring [Member] | Non-cancelable Leases, Accelerated Depreciation and Other Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges				11,600
Second quarter 2020 restructuring [Member] | Employee Severance and Pay Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs		$ 7,400
Second quarter 2020 restructuring right-of-use asset impairment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges				$ 12,300
fourth quarter 2022 restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring charges			8,100
Other Restructuring Costs			8,061
fourth quarter 2022 restructuring contract costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges			7,000
fourth quarter 2022 restructuring transition costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 1,100