Quarterly Results of Operations (Unaudited) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Apr. 01, 2018	Dec. 24, 2017	Sep. 24, 2017	Jun. 25, 2017	Mar. 26, 2017	Dec. 25, 2016	Sep. 25, 2016	Jun. 26, 2016	Apr. 01, 2018	Mar. 26, 2017	Mar. 27, 2016
Summarized quarterly financial data
Fiscal period duration	98 days	91 days	91 days	91 days	91 days	91 days	91 days	91 days	371 days	364 days	364 days
Revenues	$ 148,920,100	$ 146,260,300	$ 145,083,500	$ 140,010,800	$ 122,602,900	$ 147,198,400	$ 134,633,800	$ 128,860,000	$ 580,274,700	$ 533,295,100	$ 530,682,100
Cost of goods sold	117,381,400	116,660,500	115,160,400	110,844,000	96,665,300	117,229,800	105,878,200	101,754,000	460,046,300	421,527,300	418,716,200
Gross profit	31,538,700	29,599,800	29,923,100	29,166,800	25,937,600	29,968,600	28,755,600	27,106,000	120,228,400	111,767,800	111,965,900
Selling, general and administrative expenses	30,357,600	27,413,200	26,674,400	27,881,500	26,890,400	27,860,700	26,709,500	26,955,700	112,326,700	108,416,300	102,932,300
Restructuring charges					806,600					806,600
Operating expenses	30,357,600	27,413,200	26,674,400	27,881,500	27,697,000	27,860,700	26,709,500	26,955,700
Income from operations	1,181,100	2,186,600	3,248,700	1,285,300	(1,759,400)	2,107,900	2,046,100	150,300	7,901,700	2,544,900	9,033,600
Interest, net	89,500	114,500	156,500	68,600	(7,100)	37,100	17,200	11,400	429,100	58,600	161,300
Income before provision for income taxes	1,091,600	2,072,100	3,092,200	1,216,700	(1,752,300)	2,070,800	2,028,900	138,900	7,472,600	2,486,300	8,872,300
Provision for income taxes	(76,800)	501,900	1,318,300	533,800	(895,000)	843,100	1,034,700	58,400	2,277,200	1,041,200	3,531,800
Net income	$ 1,168,400	$ 1,570,200	$ 1,773,900	$ 682,900	$ (857,300)	$ 1,227,700	$ 994,200	$ 80,500	$ 5,195,400	$ 1,445,100	$ 5,340,500
Diluted (loss) earnings per share (in dollars per share)	$ 0.14	$ 0.19	$ 0.21	$ 0.08	$ (0.10)	$ 0.15	$ 0.12	$ 0.01	$ 0.61	$ 0.17	$ 0.65
Cash dividends declared per common share (in dollars per share)	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.80	$ 0.80	$ 0.80