Commitments (Schedule Of Future Minimum Lease Payments Under Noncancelable Operating Leases And Future Minimum Capital Lease Payments) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Commitments [Abstract]
Capital Leases, 2013	$ 1,550
Capital Leases, 2014	1,581
Capital Leases, 2015	1,613
Capital Leases, 2016	1,645
Capital Leases, 2017	1,678
Capital Leases, Thereafter	9,373
Capital Leases, Total minimum lease payments	17,440
Less: amount representing interest	6,840
Present value of minimum lease payments	10,600
Less: current installments	497	419
Capital lease obligations, less current installments	10,103	10,600
Operating Leases, 2013	6,817
Operating Leases, 2014	5,855
Operating Leases, 2015	5,492
Operating Leases, 2016	3,644
Operating Leases, 2017	866
Operating Leases, Thereafter	2,709
Operating Leases, Total minimum lease payments	$ 25,383

Name:	bhe_CommitmentsAbstract
Namespace Prefix:	bhe_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal, through the balance sheet date and due to be paid within one year (or one operating cycle, if longer) of the balance sheet date.