Acquisition of Code Plus Components, LLC (Narrative) (Details) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
	Mar. 27, 2017	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill		$ 257,134		$ 254,832
Net sales		757,700	$ 727,418
Income before income taxes		4,717	(10,696)
Acquisition costs		273	$ 0
Code Plus [Member]
Business Acquisition [Line Items]
Date of acquisition	Mar. 27, 2017
Purchase price	$ 7,100
Initial holdback	400
Earnout provision	800
Goodwill	2,300
Pre-acquisition sales				$ 14,200
Goodwill recognized expected to be deductible for tax	2,300
Customer relationships [Member] | Code Plus [Member]
Business Acquisition [Line Items]
Intangible assets	3,400
Non-compete agreements [Member] | Code Plus [Member]
Business Acquisition [Line Items]
Intangible assets	$ 500
Selling, general and administrative expenses [Member] | Code Plus [Member]
Business Acquisition [Line Items]
Acquisition costs		$ 100