CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($)	3 Months Ended
	Mar. 26, 2016	Mar. 28, 2015
CONSOLIDATED CONDENSED STATEMENTS OF COMPREHENSIVE INCOME
NET INCOME	$ 4,562,900	$ 6,054,300
Unrealized net gains (losses) on marketable securities:
Unrealized holding net gains (losses) arising during period	15,600	48,700
Reclassification adjustment for net gains included in net income		(2,300)
OTHER COMPREHENSIVE INCOME (LOSS), BEFORE TAX	15,600	46,400
Unrealized net gains/losses on marketable securities:
Unrealized holding net gains/losses arising during period	(5,900)	(18,500)
Reclassification adjustment for net gains included in net income		900
INCOME TAX (EXPENSE) BENEFIT RELATED TO ITEMS OF OTHER COMPREHENSIVE INCOME	(5,900)	(17,600)
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	9,700	28,800
COMPREHENSIVE INCOME	$ 4,572,600	$ 6,083,100