Consolidated Statements of Income - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
NET SALES	$ 1,794,872,578	$ 1,678,924,756	$ 1,543,617,706
COST OF GOODS SOLD	1,100,344,312	1,010,472,512	939,841,654
Gross profit	694,528,266	668,452,244	603,776,052
OPERATING EXPENSES:
Engineering, research and development	99,726,438	94,238,032	88,392,919
Selling, general and administrative	71,443,476	62,471,277	56,616,694
Total operating expenses	171,169,914	156,709,309	145,009,613
Income from operations	523,358,352	511,742,935	458,766,439
OTHER INCOME:
Investment income	9,442,387	4,787,128	4,990,811
Other, net	(1,004,035)	(5,969,290)	(165,794)
Total other income (expense)	8,438,352	(1,182,162)	4,825,017
Income before provision for income taxes	531,796,704	510,560,773	463,591,456
PROVISION FOR INCOME TAXES	125,004,782	162,969,497	145,121,597
NET INCOME	$ 406,791,922	$ 347,591,276	$ 318,469,859
EARNINGS PER SHARE:
Basic (in dollars per share)	$ 1.42	$ 1.21	$ 1.09
Diluted (in dollars per share)	1.41	1.19	1.08
Cash Dividends Declared per Share (in dollars per share)	$ 0.39	$ 0.355	$ 0.335