Consolidated Statements of Income (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
NET SALES	$ 1,375,501,159	$ 1,171,864,171	$ 1,099,559,521
COST OF GOODS SOLD	836,611,464	741,131,269	726,740,962
Gross profit	538,889,695	430,732,902	372,818,559
OPERATING EXPENSES:
Engineering, research and development	84,175,738	76,495,051	85,003,602
Selling, general and administrative	55,879,783	49,496,038	48,359,725
Litigation Settlement	0	0	5,000,000
Total operating expenses	140,055,521	125,991,089	138,363,327
Income from operations	398,834,174	304,741,813	234,455,232
OTHER INCOME:
Investment income	6,016,727	6,724,717	5,307,180
Other, net	10,475,589	16,597,513	9,863,188
Total other income	16,492,316	23,322,230	15,170,368
Income before provision for income taxes	415,326,490	328,064,043	249,625,600
PROVISION FOR INCOME TAXES	126,721,911	105,134,094	81,038,760
NET INCOME	$ 288,604,579	$ 222,929,949	$ 168,586,840
EARNINGS PER SHARE:
Basic (in dollars per share)	$ 0.99	$ 0.78	$ 0.59
Diluted (in dollars per share)	$ 0.98	$ 0.77	$ 0.59
Cash Dividends Declared per Share (in dollars per share)	$ 0.31	$ 0.28	$ 0.26