Consolidated Statements of Income - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
NET SALES	$ 1,543,617,706	$ 1,375,501,159	$ 1,171,864,171
COST OF GOODS SOLD	939,841,654	836,611,464	741,131,269
Gross profit	603,776,052	538,889,695	430,732,902
OPERATING EXPENSES:
Engineering, research and development	88,392,919	84,175,738	76,495,051
Selling, general and administrative	56,616,694	55,879,783	49,496,038
Total operating expenses	145,009,613	140,055,521	125,991,089
Income from operations	458,766,439	398,834,174	304,741,813
OTHER INCOME:
Investment income	4,990,811	6,016,727	6,724,717
Other, net	(165,794)	10,475,589	16,597,513
Total other income	4,825,017	16,492,316	23,322,230
Income before provision for income taxes	463,591,456	415,326,490	328,064,043
PROVISION FOR INCOME TAXES	145,121,597	126,721,911	105,134,094
NET INCOME	$ 318,469,859	$ 288,604,579	$ 222,929,949
EARNINGS PER SHARE:
Basic (in dollars per share)	$ 1.09	$ 0.99	$ 0.78
Diluted (in dollars per share)	1.08	0.98	0.77
Cash Dividends Declared per Share (in dollars per share)	$ 0.335	$ 0.31	$ 0.28