The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Goodwill and other intangible assets - Intangible assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Value	$ 302,290		$ 302,290		$ 302,290
Accumulated Amortization	83,860		83,860		67,191
Net Carrying Value	218,430		218,430		235,099
Amortization expense	8,300	$ 8,100	16,700	$ 16,200
Impairment of goodwill	0	0	0	0
Impairment of Intangible Assets	0	$ 0	$ 0	$ 0
Trademarks
Finite-Lived Intangible Assets [Line Items]
Useful Life			8 years
Gross Value	34,320		$ 34,320		34,320
Accumulated Amortization	11,310		11,310		9,167
Net Carrying Value	23,010		$ 23,010		$ 25,153
Weighted-Average Remaining Useful Life			5 years 3 months 18 days		5 years 9 months 18 days
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Value	214,320		$ 214,320		$ 214,320
Accumulated Amortization	46,711		46,711		37,564
Net Carrying Value	167,609		$ 167,609		$ 176,756
Weighted-Average Remaining Useful Life			9 years 2 months 12 days		9 years 8 months 12 days
Developed technology
Finite-Lived Intangible Assets [Line Items]
Useful Life			5 years		5 years
Gross Value	53,560		$ 53,560		$ 53,560
Accumulated Amortization	25,775		25,775		20,419
Net Carrying Value	27,785		$ 27,785		$ 33,141
Weighted-Average Remaining Useful Life			2 years 8 months 12 days		3 years 2 months 12 days
Non-competes
Finite-Lived Intangible Assets [Line Items]
Useful Life			2 years		2 years
Gross Value	90		$ 90		$ 90
Accumulated Amortization	64		64		41
Net Carrying Value	$ 26		$ 26		$ 49
Weighted-Average Remaining Useful Life			7 months 6 days		1 year 1 month 6 days
Maximum \| Trademarks
Finite-Lived Intangible Assets [Line Items]
Useful Life					8 years
Maximum \| Customer relationships
Finite-Lived Intangible Assets [Line Items]
Useful Life			12 years		12 years
Minimum \| Trademarks
Finite-Lived Intangible Assets [Line Items]
Useful Life					1 year
Minimum \| Customer relationships
Finite-Lived Intangible Assets [Line Items]
Useful Life			2 years		2 years