Reclassification Out Of Accumulated Other Comprehensive Loss (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales	$ (23,538,514)	$ (21,776,225)
Selling, general and administrative expenses	(3,646,195)	(3,750,405)
Gain on sale of equity investments	0	3,069,284
Tax (expense) benefit	1,025,000	101,000
Reclassification Out Of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, net of tax	123,750	1,530,505
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | Net Periodic Postretirement Benefit Cost [Member] | Cost of Sales [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales	108,777	(303,453)
Tax (expense) benefit	(43,669)	121,667
Reclassifications, net of tax	65,108	(181,786)
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | Net Periodic Postretirement Benefit Cost [Member] | Selling, General and Administrative Expenses [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Selling, general and administrative expenses	97,973	(215,326)
Tax (expense) benefit	(39,331)	86,333
Reclassifications, net of tax	58,642	(128,993)
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | Unrealized Net Gains on Available-for-sale Securities [Member] | Gain on Sale of Equity Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gain on sale of equity investments	0	3,069,284
Tax (expense) benefit	0	(1,228,000)
Reclassifications, net of tax	$ 0	$ 1,841,284