Retirement Benefit Plans (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jul. 04, 2015	Jun. 28, 2014	Jul. 04, 2015	Jun. 28, 2014
Significant disclosures relating to benefit plans [Abstract]
Percentage of voluntary contributions allowed to participants, maximum (in hundredths)			100.00%
Contributions made by the Company under Section 401(k)	$ 55,660	$ 50,964	$ 107,926	$ 103,455
Pension Benefits [Member]
Significant disclosures relating to benefit plans [Abstract]
Service cost	964,988	698,424	1,929,975	1,396,848
Interest cost	859,217	829,258	1,718,476	1,658,557
Expected return on plan assets	(1,287,914)	(1,202,630)	(2,575,828)	(2,405,262)
Amortization of prior service cost	54,646	54,646	109,293	109,293
Amortization of the net loss	472,728	236,032	945,456	472,065
Net periodic benefit cost	1,063,665	615,730	2,127,372	1,231,501
Contributions required by the Company in defined benefit plan			3,000,000
Contributions made by Company			1,200,000
Postretirement Benefits [Member]
Significant disclosures relating to benefit plans [Abstract]
Service cost	54,393	44,951	108,785	86,951
Interest cost	38,729	38,491	77,458	78,741
Expected return on plan assets	(22,984)	(25,156)	(45,968)	(47,406)
Amortization of prior service cost	(5,972)	(5,945)	(11,944)	(11,945)
Amortization of the net loss	4,701	0	9,402	0
Net periodic benefit cost	$ 68,867	$ 52,341	137,733	$ 106,341
Contributions required by the Company in defined benefit plan			150,000
Contributions made by Company			$ 57,000