CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) (Parenthetical) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016
Other comprehensive income/(loss):
Change in fair value marketable securities, income taxes expense (benefit)	$ 0	$ 0	$ 22,688	$ 17,135
Change in fair value of derivative instrument, income tax (expense) benefit	0	0	31,275	(10,406)
Change in pension and postretirement benefit costs, income taxes (expense)/benefit	$ 559,542	$ (105,703)	$ 338,592	$ 112,865