Business Segments (Details) (USD $)	3 Months Ended		6 Months Ended
	Sep. 28, 2014	Sep. 29, 2013	Sep. 28, 2014 Segment Category	Sep. 29, 2013
Business Segments [Abstract]
Number of reportable segments			1
Number of product categories			4
Segment Reporting Information [Line Items]
Revenues	$ 148,521,800	$ 146,526,000	$ 301,468,100	$ 290,634,800
Gross profit	35,436,000	36,492,800	70,684,800	71,930,700
Selling, general, administrative, and interest expenses	29,619,000	28,971,000	58,824,000	57,499,000
Income before provision for income taxes	5,817,200	7,522,400	11,861,200	14,431,600
Reporting Units [Member] | Public Carriers, Contractors & Program Managers [Member]
Segment Reporting Information [Line Items]
Revenues	40,853,000	40,948,000	82,271,000	78,331,000
Gross profit	7,347,000	9,015,000	14,540,000	16,909,000
Reporting Units [Member] | Private & Government System Operators [Member]
Segment Reporting Information [Line Items]
Revenues	29,446,000	31,059,000	58,450,000	58,952,000
Gross profit	8,082,000	8,377,000	15,995,000	16,178,000
Reporting Units [Member] | Commercial Dealers & Resellers [Member]
Segment Reporting Information [Line Items]
Revenues	36,780,000	36,433,000	75,064,000	72,477,000
Gross profit	10,289,000	10,093,000	20,926,000	20,340,000
Reporting Units [Member] | Retailer, Independent Dealer Agents & Carriers [Member]
Segment Reporting Information [Line Items]
Revenues	41,443,000	38,086,000	85,683,000	80,875,000
Gross profit	$ 9,718,000	$ 9,008,000	$ 19,224,000	$ 18,504,000