Operating Segment - Market Activity (Details)	3 Months Ended		6 Months Ended
	Sep. 24, 2017 USD ($)	Sep. 25, 2016 USD ($)	Sep. 24, 2017 USD ($) segment product	Sep. 25, 2016 USD ($)
Operating Segment
Number of reportable segment | segment			2
Goodwill impairment			$ 0
Number of product categories | product			4
Market unit activity
Revenues	$ 145,083,500	$ 134,633,800	$ 285,094,300	$ 263,493,800
Gross Profit	29,923,100	28,755,600	59,089,900	55,861,600
Income before provision for income taxes	3,092,200	2,028,900	4,308,900	2,167,800
Segments
Market unit activity
Directly allocable expenses	11,512,000	12,150,000	23,784,000	24,003,000
Income before provision for income taxes	18,411,000	16,606,000	35,306,000	31,859,000
Corporate
Market unit activity
Directly allocable expenses	15,319,000	14,577,000	30,997,000	29,691,000
Commercial Segment
Market unit activity
Revenues	97,606,000	81,921,000	188,730,000	162,947,000
Gross Profit	20,185,000	19,164,000	39,885,000	38,170,000
Commercial Segment | Segments
Market unit activity
Directly allocable expenses	7,796,000	7,910,000	16,318,000	16,245,000
Income before provision for income taxes	12,389,000	11,254,000	23,567,000	21,925,000
Retail Segment
Market unit activity
Revenues	47,478,000	52,713,000	96,364,000	100,547,000
Gross Profit	9,738,000	9,592,000	19,205,000	17,692,000
Retail Segment | Segments
Market unit activity
Directly allocable expenses	3,716,000	4,240,000	7,466,000	7,758,000
Income before provision for income taxes	6,022,000	5,352,000	11,739,000	9,934,000
Public Carrier
Market unit activity
Revenues	27,423,000	18,532,000	54,021,000	35,110,000
Gross Profit	3,777,000	3,236,000	7,905,000	6,253,000
Public Carrier | Commercial Segment
Market unit activity
Revenues	27,423,000	18,532,000	54,021,000	35,110,000
Gross Profit	3,777,000	3,236,000	7,905,000	6,253,000
Government
Market unit activity
Revenues	11,025,000	8,990,000	19,470,000	18,842,000
Gross Profit	2,412,000	2,092,000	4,416,000	4,232,000
Government | Commercial Segment
Market unit activity
Revenues	11,025,000	8,990,000	19,470,000	18,842,000
Gross Profit	2,412,000	2,092,000	4,416,000	4,232,000
Private System Operators
Market unit activity
Revenues	24,207,000	20,990,000	45,249,000	41,295,000
Gross Profit	5,054,000	4,613,000	9,661,000	9,179,000
Private System Operators | Commercial Segment
Market unit activity
Revenues	24,207,000	20,990,000	45,249,000	41,295,000
Gross Profit	5,054,000	4,613,000	9,661,000	9,179,000
Value-Added Resellers
Market unit activity
Revenues	34,951,000	33,409,000	69,990,000	67,700,000
Gross Profit	8,942,000	9,223,000	17,903,000	18,506,000
Value-Added Resellers | Commercial Segment
Market unit activity
Revenues	34,951,000	33,409,000	69,990,000	67,700,000
Gross Profit	8,942,000	9,223,000	17,903,000	18,506,000
Retail
Market unit activity
Revenues	47,478,000	52,713,000	96,364,000	100,547,000
Gross Profit	9,738,000	9,592,000	19,205,000	17,692,000
Retail | Retail Segment
Market unit activity
Revenues	47,478,000	52,713,000	96,364,000	100,547,000
Gross Profit	$ 9,738,000	$ 9,592,000	$ 19,205,000	$ 17,692,000