Business Segments - Segment Activity (Details)	3 Months Ended		9 Months Ended
	Dec. 30, 2018 USD ($)	Dec. 24, 2017 USD ($)	Dec. 30, 2018 USD ($) segment product	Dec. 24, 2017 USD ($)
Business Segments
Number of reportable segment | segment			2
Number of product categories | product			4
Market unit activity
Revenues	$ 152,294,500	$ 146,260,300	$ 461,850,000	$ 431,354,600
Gross Profit	30,998,700	29,599,800	93,091,500	88,689,700
Income before provision for income taxes	3,256,000	2,072,100	6,491,000	6,381,000
Segments
Market unit activity
Directly allocable expenses	12,117,000	11,317,000	37,113,000	35,101,000
Income before provision for income taxes	18,882,000	18,283,000	55,979,000	53,589,000
Corporate
Market unit activity
Directly allocable expenses	15,626,000	16,211,000	49,488,000	47,208,000
Public Carrier
Market unit activity
Revenues	33,593,000	22,721,000	113,647,000	76,742,000
Gross Profit	4,583,000	3,178,000	14,989,000	11,083,000
Value-added resellers and integrators
Market unit activity
Revenues	65,373,000	69,081,000	199,570,000	203,791,000
Gross Profit	16,013,000	16,073,000	48,842,000	48,053,000
Retail
Market unit activity
Revenues	53,329,000	54,458,000	148,633,000	150,822,000
Gross Profit	10,403,000	10,349,000	29,261,000	29,554,000
Commercial Segment
Market unit activity
Revenues	98,966,000	91,802,000	313,217,000	280,533,000
Gross Profit	20,596,000	19,251,000	63,831,000	59,136,000
Commercial Segment | Segments
Market unit activity
Directly allocable expenses	8,079,000	7,418,000	24,722,000	23,736,000
Income before provision for income taxes	12,517,000	11,833,000	39,109,000	35,400,000
Commercial Segment | Public Carrier
Market unit activity
Revenues	33,593,000	22,721,000	113,647,000	76,742,000
Gross Profit	4,583,000	3,178,000	14,989,000	11,083,000
Commercial Segment | Value-added resellers and integrators
Market unit activity
Revenues	65,373,000	69,081,000	199,570,000	203,791,000
Gross Profit	16,013,000	16,073,000	48,842,000	48,053,000
Retail Segment
Market unit activity
Revenues	53,329,000	54,458,000	148,633,000	150,822,000
Gross Profit	10,403,000	10,349,000	29,261,000	29,554,000
Retail Segment | Segments
Market unit activity
Directly allocable expenses	4,038,000	3,899,000	12,391,000	11,365,000
Income before provision for income taxes	6,365,000	6,450,000	16,870,000	18,189,000
Retail Segment | Retail
Market unit activity
Revenues	53,329,000	54,458,000	148,633,000	150,822,000
Gross Profit	$ 10,403,000	$ 10,349,000	$ 29,261,000	$ 29,554,000