Segment Information (Schedule of Segment Revenue from Product Lines) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Jun. 28, 2014	Jun. 29, 2013
Segment Reporting Information [Line Items]
Net sales	$ 152,565	$ 155,125
Audio Products [Member]
Segment Reporting Information [Line Items]
Net sales	141,161	143,666
Energy Products [Member]
Segment Reporting Information [Line Items]
Net sales	$ 11,404	$ 11,459

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

Name:	us-gaap_SalesRevenueNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration