Basis of presentation (Details) $ in Thousands	3 Months Ended
Mar. 31, 2020 USD ($) segment	Mar. 31, 2019 USD ($)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Number of operating segments \| segment	2
Number of reportable segments \| segment	2
Amortization of identifiable intangible assets	$ 210	$ 0
Cost of sales	43,685	35,159
Service
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cost of sales	$ 12,646	10,268
Reclassification
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Amortization of identifiable intangible assets		300
Reclassification \| Service
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cost of sales		$ 300

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.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

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The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
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-Paragraph 2
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