Operating Segment - Market Activity (Details)	3 Months Ended								12 Months Ended			30 Months Ended
	Mar. 26, 2017 USD ($)	Dec. 25, 2016 USD ($)	Sep. 25, 2016 USD ($)	Jun. 26, 2016 USD ($)	Mar. 27, 2016 USD ($)	Dec. 27, 2015 USD ($)	Sep. 27, 2015 USD ($)	Jun. 28, 2015 USD ($)	Mar. 26, 2017 USD ($) segment product	Mar. 27, 2016 USD ($)	Mar. 29, 2015 USD ($)	Mar. 26, 2017 item
Operating Segment
Number of reportable segment | segment									1
Number of system operator markets reported | item												2
Number of product categories | product									4
Market unit activity
Revenues	$ 122,602,900	$ 147,198,400	$ 134,633,800	$ 128,860,000	$ 114,154,100	$ 139,510,700	$ 142,353,300	$ 134,664,000	$ 533,295,100	$ 530,682,100	$ 549,619,000
Gross Profit	$ 25,937,600	$ 29,968,600	$ 28,755,600	$ 27,106,000	$ 23,018,900	$ 29,453,400	$ 30,511,700	$ 28,981,900	111,767,800	111,965,900	117,638,500
Public Carriers, Contractors & Program Managers
Market unit activity
Revenues									82,015,000	89,171,000	127,426,000
Gross Profit									13,707,000	15,155,000	20,915,000
Government System Operators
Market unit activity
Revenues									36,676,000	33,009,000	31,495,000
Gross Profit									8,235,000	7,713,000	7,535,000
Private System Operators
Market unit activity
Revenues									93,869,000	85,563,000	86,725,000
Gross Profit									21,648,000	20,601,000	20,866,000
Commercial Dealers & Resellers
Market unit activity
Revenues									126,326,000	129,986,000	134,195,000
Gross Profit									34,289,000	33,781,000	34,948,000
Retailer, Independent Dealer Agents & Carriers
Market unit activity
Revenues									194,409,000	192,953,000	169,778,000
Gross Profit									$ 33,889,000	$ 34,716,000	$ 33,375,000