Ransomware incident (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disclosure Text Block Supplement [Abstract]
Ransomware related incident costs, net	$ 0	$ 0	$ (3,944)

The amount of costs (recovery) associated with systems affected by a ransomware incident that encrypted information on our systems and disrupted customer and employee access to our systems and services.

No definition available.

Name:	bhe_RansomwareRelatedIncidentCostsNet
Namespace Prefix:	bhe_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration