Business Segments - Segment Activity (Details)	3 Months Ended	6 Months Ended
Sep. 30, 2018 USD ($)	Sep. 24, 2017 USD ($)	Sep. 30, 2018 USD ($) segment product	Sep. 24, 2017 USD ($)
Business Segments
Number of reportable segment \| segment			2
Number of product categories \| product			4
Market unit activity
Revenues	$ 158,636,100	$ 145,083,500	$ 309,555,500	$ 285,094,300
Gross Profit	31,394,700	29,923,100	62,092,800	59,089,900
Income before provision for income taxes	1,672,600	3,092,200	3,235,000	4,308,900
Segments
Market unit activity
Directly allocable expenses	13,106,000	11,512,000	24,996,000	23,784,000
Income before provision for income taxes	18,289,000	18,411,000	37,097,000	35,306,000
Corporate
Market unit activity
Directly allocable expenses	16,616,000	15,319,000	33,862,000	30,997,000
Public Carrier
Market unit activity
Revenues	39,694,000	27,423,000	80,054,000	54,021,000
Gross Profit	4,780,000	3,777,000	10,406,000	7,905,000
Integrators and value-added resellers
Market unit activity
Revenues	68,650,000	70,183,000	134,197,000	134,709,000
Gross Profit	16,912,000	16,408,000	32,829,000	31,980,000
Retail
Market unit activity
Revenues	50,292,000	47,478,000	95,304,000	96,364,000
Gross Profit	9,703,000	9,738,000	18,858,000	19,205,000
Commercial Segment
Market unit activity
Revenues	108,344,000	97,606,000	214,251,000	188,730,000
Gross Profit	21,692,000	20,185,000	43,235,000	39,885,000
Commercial Segment \| Segments
Market unit activity
Directly allocable expenses	8,562,000	7,796,000	16,643,000	16,318,000
Income before provision for income taxes	13,130,000	12,389,000	26,592,000	23,567,000
Commercial Segment \| Public Carrier
Market unit activity
Revenues	39,694,000	27,423,000	80,054,000	54,021,000
Gross Profit	4,780,000	3,777,000	10,406,000	7,905,000
Commercial Segment \| Integrators and value-added resellers
Market unit activity
Revenues	68,650,000	70,183,000	134,197,000	134,709,000
Gross Profit	16,912,000	16,408,000	32,829,000	31,980,000
Retail Segment
Market unit activity
Revenues	50,292,000	47,478,000	95,304,000	96,364,000
Gross Profit	9,703,000	9,738,000	18,858,000	19,205,000
Retail Segment \| Segments
Market unit activity
Directly allocable expenses	4,544,000	3,716,000	8,353,000	7,466,000
Income before provision for income taxes	5,159,000	6,022,000	10,505,000	11,739,000
Retail Segment \| Retail
Market unit activity
Revenues	50,292,000	47,478,000	95,304,000	96,364,000
Gross Profit	$ 9,703,000	$ 9,738,000	$ 18,858,000	$ 19,205,000

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