CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) (Parenthetical) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Other comprehensive income/(loss):
Change in fair value of marketable securities, tax benefit	$ 679	$ 3,008	$ (2,063)	$ (463)
Change in fair value of interest rate swap and marketable securities, tax benefit	48,169	69,817	582,673	45,197
Change in pension and postretirement benefit costs, income tax expense	$ 81,142	$ 141,876	$ 162,285	$ 70,938