Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Deferred income tax liabilities:
Plant, property and equipment	$ 604,271	$ 536,759
Total	604,271	536,759
Deferred income tax assets:
Asset valuations	720,189	677,994
Operating loss carryforwards and credits	121,658	110,110
Pension	227,681	189,920
Foreign tax credit	186,504	186,504
Other	593,140	753,219
Total	1,849,172	1,917,747
Net deferred income tax asset before valuation allowance	1,244,901	1,380,988
Valuation allowance	(74,552)	(110,110)
Net deferred income tax asset	$ 1,170,349	$ 1,270,878