Reclassifications Out Of Accumulated Other Comprehensive Loss (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales, reclassifications	$ 34,997,608	$ 30,734,889	$ 88,847,365	$ 84,084,713
Selling, general and administrative expenses, reclassifications	3,900,586	3,715,906	11,448,710	11,002,205
Gain on sale of equity investments, reclassifications	0	3,605,597	3,881,872	4,173,141
Less: Income tax expense (benefit)	613,000	1,715,000	1,890,000	2,538,000
Reclassifications, net of tax	1,972,388	2,260,374	1,911,920	3,357,896
Reclassification Out Of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Less: Income tax expense (benefit)	(204,000)	1,231,000	939,000	1,047,000
Reclassifications, net of tax	(307,028)	1,853,684	1,409,790	1,573,799
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | Net Periodic Pension And Postretirement [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales, reclassifications	(305,605)	(309,371)	(916,813)	(921,935)
Selling, general and administrative expenses, reclassifications	(205,423)	(211,542)	(616,269)	(630,407)
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | Unrealized Net Gains On Available-For-Sale Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gain on sale of equity investments, reclassifications	$ 0	$ 3,605,597	$ 3,881,872	$ 4,173,141