Goodwill and other intangible assets - Intangible Assets (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Gross Value					$ 303,401,000
Accumulated Amortization (in thousands)	$ 129,521,000		$ 129,521,000		100,523,000
Net Carrying Value					202,878,000
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross Value	406,271,000		406,271,000
Net Carrying Value	276,750,000		276,750,000		$ 202,878,000
Amortization expense	12,200,000	$ 8,300,000	29,100,000	$ 25,000,000
Goodwill and Intangible Asset Impairment	0	$ 0	0	$ 0
IPR&D
Indefinite-lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	400,000		400,000
Trademarks
Finite-Lived Intangible Assets [Line Items]
Useful Life					8 years
Gross Value	34,690,000		34,690,000		$ 34,320,000
Accumulated Amortization (in thousands)	16,683,000		16,683,000		13,454,000
Net Carrying Value	18,007,000		$ 18,007,000		$ 20,866,000
Weighted‑ Average Remaining Useful Life			4 years 1 month 6 days		4 years 9 months 18 days
Trademarks | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life			3 years
Trademarks | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life			8 years
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Value	249,483,000		$ 249,483,000		$ 214,428,000
Accumulated Amortization (in thousands)	70,239,000		70,239,000		55,810,000
Net Carrying Value	179,244,000		$ 179,244,000		$ 158,618,000
Weighted‑ Average Remaining Useful Life			8 years 6 months		8 years 8 months 12 days
Customer relationships | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life			2 years		2 years
Customer relationships | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life			12 years		12 years
Developed technology
Finite-Lived Intangible Assets [Line Items]
Useful Life					5 years
Gross Value	116,158,000		$ 116,158,000		$ 54,563,000
Accumulated Amortization (in thousands)	41,956,000		41,956,000		31,173,000
Net Carrying Value	74,202,000		$ 74,202,000		$ 23,390,000
Weighted‑ Average Remaining Useful Life			5 years 2 months 12 days		2 years 3 months 18 days
Developed technology | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life			5 years
Developed technology | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life			6 years 6 months
Non‑competes
Finite-Lived Intangible Assets [Line Items]
Useful Life					2 years
Gross Value	1,796,000		$ 1,796,000		$ 90,000
Accumulated Amortization (in thousands)	264,000		264,000		86,000
Net Carrying Value	1,532,000		$ 1,532,000		$ 4,000
Weighted‑ Average Remaining Useful Life			2 years 3 months 18 days		1 month 6 days
Non‑competes | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life			2 years
Non‑competes | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life			2 years 6 months
Order backlog
Finite-Lived Intangible Assets [Line Items]
Useful Life			2 years 6 months
Gross Value	3,744,000		$ 3,744,000
Accumulated Amortization (in thousands)	379,000		379,000
Net Carrying Value	$ 3,365,000		$ 3,365,000
Weighted‑ Average Remaining Useful Life			2 years 3 months 18 days