Consolidated Statements of Shareholders' Equity - USD ($)	Common Stock [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balances at Dec. 28, 2013	$ 28,621,582	$ (19,105,723)	$ 83,006,671	$ (11,017,679)	$ 81,504,851
Balances (in shares) at Dec. 28, 2013	8,916,897	(2,694,729)
Net income			7,661,476		7,661,476
Cash dividends declared			(2,987,480)		(2,987,480)
Currency translation adjustment				(1,128,327)	(1,128,327)
Change in pension and other postretirement benefit costs, net of taxes (expense)/benefit				(10,386,089)	(10,386,089)
Issuance of Common Stock upon the exercise of stock options	$ 271,600				271,600
Issuance of Common Stock upon the exercise of stock options (in shares)	20,000
Tax benefit from disqualifying dispositions of incentive stock options	$ 8,882				8,882
Issuance of Common Stock for directors' fees	$ 29,994				29,994
Issuance of Common Stock for directors' fees (in shares)	1,845
Balances at Jan. 03, 2015	$ 28,932,058	$ (19,105,723)	87,680,667	(22,532,095)	74,974,907
Balances (in shares) at Jan. 03, 2015	8,938,742	(2,694,729)
Net income			5,727,043		5,727,043
Cash dividends declared			(2,810,669)		(2,810,669)
Currency translation adjustment				(2,009,277)	(2,009,277)
Change in pension and other postretirement benefit costs, net of taxes (expense)/benefit				3,458,060	3,458,060
Tax benefit from disqualifying dispositions of incentive stock options					0
Issuance of Common Stock for directors' fees	$ 64,992				64,992
Issuance of Common Stock for directors' fees (in shares)	3,719
Balances at Jan. 02, 2016	$ 28,997,050	$ (19,105,723)	90,597,041	(21,083,312)	79,405,056
Balances (in shares) at Jan. 02, 2016	8,942,461	(2,694,729)
Net income			7,785,323		7,785,323
Cash dividends declared			(2,751,148)		(2,751,148)
Currency translation adjustment				(1,010,983)	(1,010,983)
Change in pension and other postretirement benefit costs, net of taxes (expense)/benefit				(1,110,306)	(1,110,306)
Tax benefit from disqualifying dispositions of incentive stock options					0
Issuance of Common Stock for directors' fees	$ 149,572				149,572
Issuance of Common Stock for directors' fees (in shares)	8,366
Balances at Dec. 31, 2016	$ 29,146,622	$ (19,105,723)	$ 95,631,216	$ (23,204,601)	$ 82,467,514
Balances (in shares) at Dec. 31, 2016	8,950,827	(2,694,729)