Other intangible assets (Details 2) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net (excluding goodwill)	$ 22,241	$ 26,376	$ 22,241	$ 26,376	$ 25,496
Amortization of intangible assets	1,200	2,100	3,900	6,800
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	29,423	27,551	29,423	27,551	28,836
Intangible assets, less accumulated amortization	9,705	5,958	9,705	5,958	6,887
Intangible assets, net (excluding goodwill)	19,718	21,593	19,718	21,593	21,949
Noncompete agreements
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	3,991	3,941	3,991	3,941	3,941
Intangible assets, less accumulated amortization	2,710	2,176	2,710	2,176	2,309
Intangible assets, net (excluding goodwill)	1,281	1,765	1,281	1,765	1,632
Other intangible assets
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	11,957	12,853	11,957	12,853	12,927
Intangible assets, less accumulated amortization	10,715	9,835	10,715	9,835	11,012
Intangible assets, net (excluding goodwill)	$ 1,242	$ 3,018	$ 1,242	$ 3,018	$ 1,915