Gentex (GNTX) 10-K 26 Feb 14 2013 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2013	Feb. 07, 2014	Jun. 30, 2013
Document And Entity Information [Abstract]	'	'	'
Entity Registrant Name	'GENTEX CORP	'	'
Entity Central Index Key	'0000355811	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Document Type	'10-K	'	'
Document Period End Date	31-Dec-13	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Amendment Flag	'false	'	'
Entity Common Stock, Shares Outstanding	'	145,652,257	'
Entity Public Float	'	'	$3,206,059,559
Entity Current Reporting Status	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Well-known Seasoned Issuer	'Yes	'	'

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2013	Dec. 31, 2012
ASSETS	'	'
Cash and cash equivalents	$309,591,724	$389,678,664
Short-term investments	0	60,802,856
Accounts receivable	143,046,590	109,579,693
Inventories	120,074,164	159,930,266
Prepaid expenses and other	28,473,764	24,671,561
Total current assets	601,186,242	744,663,040
PLANT AND EQUIPMENT:	'	'
Land, buildings and improvements	223,191,567	198,156,137
Machinery and equipment	507,768,233	472,844,579
Construction-in-process	41,481,572	45,092,001
Total Plant and Equipment	772,441,372	716,092,717
Less- Accumulated depreciation	-415,420,147	-366,154,545
Net Plant and Equipment	357,021,225	349,938,172
OTHER ASSETS:	'	'
Goodwill	307,365,845	0
Long-term investments	107,005,522	141,834,034
Intangible Assets, net	366,175,000	0
Patents and other assets, net	25,334,600	29,256,089
Total other assets	805,880,967	171,090,123
TOTAL ASSETS	1,764,088,434	1,265,691,335
LIABILITIES AND SHAREHOLDERS’ INVESTMENT	'	'
Accounts payable	56,510,321	43,200,002
Accrued liabilities:	'	'
Salaries, wages and vacation	7,770,868	7,188,092
Income taxes	13,316,102	1,582,570
Royalties	9,374,449	9,889,708
Dividends declared	20,380,923	18,599,926
Current portion of Long Term Debt	7,500,000	0
Other	5,127,751	7,497,144
Total current liabilities	119,980,414	87,957,442
LONG TERM DEBT	265,625,000	0
DEFERRED INCOME TAXES	50,879,337	56,773,337
TOTAL LIABILITIES	436,484,751	144,730,779
SHAREHOLDERS’ INVESTMENT:	'	'
Preferred stock, no par value, 5,000,000 shares authorized; none issued or outstanding	0	0
Common stock, par value $.06 per share; 200,000,000 shares authorized; 145,578,023 and 143,076,357 shares issued and outstanding in 2013 and 2012 respectively.	8,734,681	8,584,581
Additional paid-in capital	478,865,778	418,766,010
Retained earnings	818,027,861	676,039,254
Accumulated other comprehensive income:	'	'
Unrealized gain on investments	19,467,441	15,111,778
Cumulative translation adjustment	2,507,922	2,458,933
Total shareholders’ investment	1,327,603,683	1,120,960,556
TOTAL LIABILITES AND SHAREHOLDERS' INVESTMENT	$1,764,088,434	$1,265,691,335

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]	'	'
Preferred stock, par value (in dollars per share)	$0	$0
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$0.06	$0.06
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	145,578,023	143,076,357
Common stock, shares outstanding (in shares)	145,578,023	143,076,357

Consolidated_Statements_of_Inc

Consolidated Statements of Income (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Statement [Abstract]	'	'	'
NET SALES	$1,171,864,171	$1,099,559,521	$1,023,762,049
COST OF GOODS SOLD	741,131,269	726,740,962	662,181,714
Gross profit	430,732,902	372,818,559	361,580,335
OPERATING EXPENSES:	'	'	'
Engineering, research and development	76,495,051	85,003,602	81,634,158
Selling, general and administrative	49,496,038	48,359,725	48,578,252
Litigation Settlement	0	5,000,000	0
Total operating expenses	125,991,089	138,363,327	130,212,410
Income from operations	304,741,813	234,455,232	231,367,925
OTHER INCOME:	'	'	'
Investment income	6,724,717	5,307,180	4,165,809
Other, net	16,597,513	9,863,188	8,898,077
Total other income	23,322,230	15,170,368	13,063,886
Income before provision for income taxes	328,064,043	249,625,600	244,431,811
PROVISION FOR INCOME TAXES	105,134,094	81,038,760	79,763,583
NET INCOME	$222,929,949	$168,586,840	$164,668,228
EARNINGS PER SHARE:	'	'	'
Basic (in dollars per share)	$1.55	$1.18	$1.16
Diluted (in dollars per share)	$1.55	$1.17	$1.14
Cash Dividends Declared per Share (in dollars per share)	$0.56	$0.52	$0.48

Consolidated_Statement_of_Comp

Consolidated Statement of Comprehensive Income (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Comprehensive Income [Abstract]	'	'	'
Net Income	$222,929,949	$168,586,840	$164,668,228
Other comprehensive income (loss) before tax:	'	'	'
Foreign currency translation adjustments	48,989	328,976	1,563,054
Unrealized gains (losses) on available-for sales securities, net	6,701,020	7,230,048	-17,442,698
Other comprehensive income (loss), before tax	6,750,009	7,559,024	-15,879,644
Provision for income taxes related to components of other comprehensive income	2,345,357	2,530,516	-6,104,944
Other comprehensive Income (loss), net of tax	4,404,652	5,028,508	-9,774,700
Comprehensive Income	$227,334,601	$173,615,348	$154,893,528

Consolidated_Statement_of_Shar

Consolidated Statement of Shareholders' Investment (USD $)	3 Months Ended				12 Months Ended
	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Beginning balance (in shares)	'	143,076,357	'	'	143,076,357	'	'
Beginning balance	'	$1,120,960,556	'	$1,027,118,521	$1,120,960,556	$1,027,118,521	$893,530,826
Issuance of common stock and the tax benefit of stock plan transactions	'	'	'	'	42,822,635	12,208,881	33,304,762
Repurchases of common stock	'	'	'	'	'	-33,716,725	'
Stock-based compensation expense related to stock options, employee stock purchases and restricted stock	'	'	'	'	17,427,233	16,433,837	14,197,557
Dividends declared ($.48, $.52, and $.56 per share for the years ended December 31, 2011, 2012 and 2013 respectively)	'	'	'	'	-80,941,342	-74,699,306	-68,808,152
Net Income	69,881,000	45,431,000	39,599,000	46,345,000	222,929,949	168,586,840	164,668,228
Other comprehensive income	'	'	'	'	4,404,652	5,028,508	-9,774,700
Ending balance (in shares)	145,578,023	'	143,076,357	'	145,578,023	143,076,357	'
Ending balance	1,327,603,683	'	1,120,960,556	'	1,327,603,683	1,120,960,556	1,027,118,521
Common Stocks	'	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Beginning balance (in shares)	'	143,076,357	'	144,069,563	143,076,357	144,069,563	142,292,127
Beginning balance	'	8,584,581	'	8,644,174	8,584,581	8,644,174	8,537,528
Issuance of common stock and the tax benefit of stock plan transactions (in shares)	'	'	'	'	2,501,666	978,623	1,777,436
Issuance of common stock and the tax benefit of stock plan transactions	'	'	'	'	150,100	58,717	106,646
Repurchases of common stock (in shares)	'	'	'	'	'	-1,971,829	'
Repurchases of common stock	'	'	'	'	'	-118,310	'
Ending balance (in shares)	145,578,023	'	143,076,357	'	145,578,023	143,076,357	144,069,563
Ending balance	8,734,681	'	8,584,581	'	8,734,681	8,584,581	8,644,174
Additional Paid-In Capital	'	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Beginning balance	'	418,766,010	'	395,229,891	418,766,010	395,229,891	347,834,218
Issuance of common stock and the tax benefit of stock plan transactions	'	'	'	'	42,672,535	12,150,164	33,198,116
Repurchases of common stock	'	'	'	'	'	-5,047,882	'
Stock-based compensation expense related to stock options, employee stock purchases and restricted stock	'	'	'	'	17,427,233	16,433,837	14,197,557
Ending balance	478,865,778	'	418,766,010	'	478,865,778	418,766,010	395,229,891
Retained Earnings	'	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Beginning balance	'	676,039,254	'	610,702,253	676,039,254	610,702,253	514,842,177
Repurchases of common stock	'	'	'	'	'	-28,550,533	'
Dividends declared ($.48, $.52, and $.56 per share for the years ended December 31, 2011, 2012 and 2013 respectively)	'	'	'	'	-80,941,342	-74,699,306	-68,808,152
Net Income	'	'	'	'	222,929,949	168,586,840	164,668,228
Ending balance	818,027,861	'	676,039,254	'	818,027,861	676,039,254	610,702,253
Accumulated Other Comprehensive Income (Loss)	'	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Beginning balance	'	17,570,711	'	12,542,203	17,570,711	12,542,203	22,316,903
Other comprehensive income	'	'	'	'	4,404,652	5,028,508	-9,774,700
Ending balance	$21,975,363	'	$17,570,711	'	$21,975,363	$17,570,711	$12,542,203

Consolidated_Statement_of_Shar1

Consolidated Statement of Shareholders' Investment (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Stockholders' Equity [Abstract]	'	'	'
Dividends declared per share (in dollars per share)	$0.56	$0.52	$0.48

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net Cash Provided by (Used in) Operating Activities [Abstract]	'	'	'
Net Income	$222,929,949	$168,586,840	$164,668,228
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'
Depreciation and amortization	62,854,155	50,179,823	42,634,684
Gain on disposal of assets	-54,520	-419,382	0
Loss on disposal of assets	2,162,610	952,190	992,876
Gain on sale of investments	-19,012,429	-9,584,288	-15,787,691
Loss on sale of investments	882,918	1,216,027	9,134,183
Deferred income taxes	-7,726,800	843,484	13,942,674
Stock based compensation expense related to employee stock options, employee stock purchases and restricted stock	17,427,233	16,433,837	14,197,557
Excess tax benefits from stock based compensation	-4,445,064	-815,651	-5,362,501
Change in operating assets and liabilities:	'	'	'
Accounts receivable	-22,347,450	810,022	-14,742,103
Inventories	39,856,102	28,823,046	-88,024,582
Prepaid expenses and other	-2,374,913	14,868,742	-6,954,317
Accounts payable	13,310,319	-22,270,571	25,175,109
Accrued liabilities	13,876,720	8,221,935	1,794,548
Net cash provided by operating activities	317,338,830	257,846,054	141,668,665
Activity in available-for-sale securities:	'	'	'
Sales proceeds	82,862,644	38,831,234	107,763,498
Maturities and calls	98,142,408	75,652,000	104,375,000
Purchases	-60,543,153	-112,545,415	-196,365,327
Plant and equipment additions	-55,380,457	-117,474,449	-120,177,730
Proceeds from sale of plant and equipment	386,399	1,064,614	179,212
Acquisition of businesses, net of cash acquired	-698,150,900	0	0
Decrease (increase) in other assets	-573,560	-17,602,228	698,357
Net cash provided by (used for) investing activities	-633,256,619	-132,074,244	-103,526,990
CASH FLOWS FROM FINANCING ACTIVITIES:	'	'	'
Proceeds from borrowings on Credit Agreement	275,000,000	0	0
Repayment of long-term debt	-1,875,000	0	0
Deferred financing costs	-956,441	0	0
Issuance of common stock from stock plan transactions	38,377,571	12,208,881	33,304,764
Cash dividends paid	-79,160,345	-73,387,727	-67,171,939
Repurchases of common stock	0	-33,716,725	0
Excess tax benefits from stock based compensation	4,445,064	815,651	5,362,501
Net cash provided by (used for) financing activities	235,830,849	-94,079,920	-28,504,674
NET INCREASE IN CASH AND CASH EQUIVALENTS	-80,086,940	31,691,890	9,637,001
CASH AND CASH EQUIVALENTS, Beginning of year	389,678,664	357,986,774	348,349,773
CASH AND CASH EQUIVALENTS, End of year	$309,591,724	$389,678,664	$357,986,774

Summary_of_Significant_Account

Summary of Significant Accounting and Reporting Policies	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Summary Of Significant Accounting And Reporting Policies	'
	SUMMARY OF SIGNIFICANT ACCOUNTING AND REPORTING POLICIES
	The Company
	Gentex Corporation designs and manufactures automatic-dimming rearview mirrors and electronics for the automotive industry, dimmable aircraft windows for the aviation industry, and commercial smoke alarms and signaling devices for the fire protection industry. The Company’s largest business segment involves designing, developing, manufacturing and marketing interior and exterior auto-dimming automotive rearview mirrors that utilize proprietary electrochromic technology to dim in proportion to the amount of headlight glare from trailing vehicle headlamps. The Company ships its product to all of the major automotive producing regions worldwide, which it supports with numerous sales, engineering and distribution locations worldwide.
	A substantial portion of the Company’s net sales and accounts receivable result from transactions with domestic and foreign automotive manufacturers and Tier 1 suppliers. The Company’s fire protection products are primarily sold to domestic distributors and original equipment manufacturers of fire and security systems. Aircraft windows are sold for use by aircraft manufacturers. The Company does not require collateral or other security for trade accounts receivable.
	Significant accounting policies of the Company not described elsewhere are as follows:
	Consolidation
	The consolidated financial statements include the accounts of Gentex Corporation and all of its wholly-owned subsidiaries (together the “Company”). All significant intercompany accounts and transactions have been eliminated.
	Cash Equivalents
	Cash equivalents consist of funds invested in bank accounts and money market funds that have daily liquidity.
	Allowance For Doubtful Accounts
	The Company bases its allowances for doubtful accounts related to receivables on historical credit and collections experience, and the specific identification of other potential problems, including the economic climate. Actual collections can differ, requiring adjustments to the allowances. Individual accounts receivable balances are evaluated on a monthly basis, and those balances considered uncollectible are charged to the allowance. Collections of amounts previously written off are recorded as an increase to the allowance.
	The following table presents the activity in the Company’s allowance for doubtful accounts:
		Beginning		Net				Deductions				Ending
		Balance		Additions/				and Other				Balance
				(Reductions)				Adjustments
				to Costs and
				Expenses
	Year Ended December 31, 2013:
	Allowance for Doubtful Accounts	$	3,400,000	$	—			$	197,612			$	3,202,388
	Year Ended December 31, 2012:
	Allowance for Doubtful Accounts	$	3,400,000	$	(577	)		577*				$	3,400,000
	Year Ended December 31, 2011:
	Allowance for Doubtful Accounts	$	4,300,000	$	(802,929	)		$	(97,071	)*		$	3,400,000
	*Represents excess recoveries and other adjustments over accounts written off.
	The Company’s overall allowance for doubtful accounts primarily relates to financially distressed Tier 1 automotive customers. The Company continues to work with these financially distressed customers in collecting past due balances.
	Investments
	The Company follows the provisions of ASC 820, “Fair Value Measurements and Disclosures” for its financial assets and liabilities, and for its non-financial assets and liabilities subject to fair value measurements. ASC 820 provides a framework for measuring the fair value of assets and liabilities. This framework is intended to provide increased consistency in how fair value determinations are made under various existing accounting standards that permit, or in some cases, require estimates of fair-market value. This standard also expanded financial statement disclosure requirements about a company’s use of fair-value measurements, including the effect of such measure on earnings. The cost of securities sold is based on the specific identification method.
	The Company’s investment securities (common stocks and mutual funds) are classified as available for sale and are stated at fair value based on quoted market prices, and as such are classified as Level 1 assets. The Company determines the fair value of its U.S. Treasury Notes, Government Securities and Corporate Bonds by utilizing monthly valuation statements that are provided by its broker, and the Company utilizes third party pricing sources to validate such statements. The broker determines the investment valuation by utilizing the bid price in the market. As such, these investments are classified as Level 2 assets.
	Assets or liabilities that have recurring fair value measurements are shown below as of December 31, 2013 and December 31, 2012:
				Fair Value Measurements at Reporting Date Using
		Total as of		Quoted Prices in				Significant Other				Significant
				Active Markets				Observable				Unobservable
				for Identical				Inputs				Inputs
				Assets
	Description	31-Dec-13		(Level I)				(Level 2)				(Level 3)
	Cash & Cash Equivalents	$	309,591,724	$	309,591,724			$	—			$	—
	Long-Term Investments:
	Common Stocks	33,282,439		33,282,439				—				—
	Mutual Funds – Equity	73,723,083		73,723,083				—				—
	Total	$	416,597,246	$	416,597,246			$	—			$	—
				Fair Value Measurements at Reporting Date Using
		Total as of		Quoted Prices in				Significant Other				Significant
				Active Markets				Observable				Unobservable
				for Identical				Inputs				Inputs
				Assets
	Description	December 31, 2012		(Level I)				(Level 2)				(Level 3)
	Cash & Cash Equivalents	$	389,678,664	$	389,678,664			$	—			$	—
	Short-Term Investments:
	Certificate of Deposit	510,881		—				510,881				—
	Government Securities	38,522,471		—				38,522,471				—
	U.S. Treasury Notes	15,020,350		—				15,020,350				—
	Corporate Bonds	6,563,228		—				6,563,228				—
	Other	185,926		185,926				—				—
	Long-Term Investments:
	Corporate Bonds	2,180,780		—				2,180,780				—
	Common Stocks	53,283,201		53,283,201				—				—
	Mutual Funds – Equity	86,109,053		86,109,053				—				—
	Other – Equity	261,000		261,000				—				—
	Total	$	592,315,554	$	529,517,844			$	62,797,710			$	—
	The amortized cost, unrealized gains and losses, and market value of investment securities are shown as of December 31, 2013 and 2012:
		Unrealized
	2013	Cost		Gains					Losses					Market Value
	Long-Term Investments:
Common Stocks	22,799,035		10,532,007					(48,603		)			33,282,439
Mutual Funds-Equity	54,256,577		19,466,506					—					73,723,083
Total	$	77,055,612	$	29,998,513		—		$	(48,603	)	—		$	107,005,522
	Unrealized
2012	Cost		Gains				Losses				Market Value
Short-Term Investments:
Certificate of Deposit	$	510,881	$	—			$	—			$	510,881
Government Securities	$	38,514,411	$	9,004			$	(944	)		$	38,522,471
U.S. Treasury Notes	15,018,810		2,602				(1,062		)		15,020,350
Corporate Bonds	6,529,758		33,470				—				6,563,228
Other	185,926		—				—				185,926
Long-Term Investments:
Corporate Bonds	2,174,948		5,832				—				2,180,780
Common Stocks	40,893,121		12,781,501				(391,421		)		53,283,201
Mutual Funds-Equity	75,321,640		11,082,714				(295,301		)		86,109,053
Other-Equity	238,506		22,494				—				261,000
Total	$	179,388,001	$	23,937,617			(688,728		)		$	202,636,890
Unrealized losses on investments as of December 31, 2013 are as follows:
	Aggregate Unrealized Losses		Aggregate Fair Value
Less than one year	$	48,603	$	1,886,080
Unrealized losses on investments as of December 31, 2012 are as follows:
	Aggregate Unrealized Losses		Aggregate Fair Value
Less than one year	$	688,728	$	22,887,686
ASC 320, “Accounting for Certain Investments in Debt and Equity Securities,” as amended and interpreted, provides guidance on determining when an investment is other-than-temporarily impaired. The Company reviews its fixed income and equity investment portfolio for any unrealized losses that would be deemed other-than-temporary and require the recognition of an impairment loss in income. If the cost of an investment exceeds its fair value, the Company evaluates, among other factors, general market conditions, the duration and extent to which the fair value is less than cost, and the Company’s intent and ability to hold the investments. Management also considers the type of security, related-industry and sector performance, as well as published investments ratings and analyst reports, to evaluate its portfolio. Once a decline in fair value is determined to be other-than-temporary, an impairment charge is recorded and new cost basis in the investment is established. If market, industry, and/or investee conditions deteriorate, the Company may incur future impairments. No investments were considered to be other-than-temporary impaired in 2013 and 2012.
Fair Value of Financial Instruments
The Company’s financial instruments consist of cash and cash equivalents, investments, accounts receivable accounts payable, short and long term debt. The Company’s estimate of the fair values of these financial instruments approximates their carrying amounts at December 31, 2013 and 2012.
Inventories
Inventories include material, direct labor and manufacturing overhead and are valued at the lower of first-in, first-out (FIFO) cost or market. Inventories consisted of the following as of December 31, 2013 and 2012.
	2013		2012
Raw materials	$	75,081,810	$	114,750,525
Work-in-process	21,409,976		24,588,734
Finished goods	23,582,378		20,591,007
Total Inventory	$	120,074,164	$	159,930,266
Allowances for slow-moving and obsolete inventories were $6.9 million and $7.8 million at December 31, 2013 and 2012. The year-over-year decrease in the allowance was primarily the result of reductions in raw materials inventory.
Plant and Equipment
Plant and equipment are stated at cost. Depreciation and amortization are computed for financial reporting purposes using the straight-line method, with estimated useful lives of 7 to 40 years for buildings and improvements, and 3 to 10 years for machinery and equipment. Depreciation expense was approximately $55.0 million, $48.5 million and $41.6 million in 2013, 2012 and 2011, respectively.
Impairment of Disposal of Long-Lived Assets
The Company reviews long-lived assets, including property, plant and equipment and other intangible assets with definite lives, for impairment whenever events or changes in circumstances indicate that the asset’s carrying amount of an asset may not be recoverable. The Company conducts its long-lived asset impairment analysis in accordance with ASC 360-10-15, “Impairment or Disposal of Long-Lived Assets.” ASC 360-10-15 requires the Company to group assets and liabilities at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities and evaluate the asset group against the sum of the undiscounted future cash flows. If the undiscounted cash flows do not indicate the carrying amount of the asset is recoverable, an impairment charge is measured as the amount by which the carrying amount of the asset group exceeds its fair value based on discounted cash flow analysis or appraisals.
Patents
The Company’s policy is to capitalize costs incurred to obtain patents. The cost of patents is amortized over their useful lives. The cost of patents in process is not amortized until issuance. The Company periodically obtains intellectual property rights, in the ordinary course of business, and the cost of the rights are amortized over their useful lives.
Goodwill and Intangible Assets
Goodwill represents the excess of fair value of assets acquired and liabilities assumed as of the acquisition date. In accordance with accounting guidance related to goodwill and other intangible assets, the Company will test for impairment of goodwill and indefinite-lived intangible assets annually in the fourth quarter and in certain situations between those annual dates, if interim indicators of impairment arise. Indefinite-lived intangible assets will be tested for impairment annually in the fourth quarter, by comparing the estimated fair value of the indefinite-lived intangible asset to the carrying value using a discounted cash flow approach. Intangible assets with a definite life are amortized over their useful life, which is the period over which the asset is expected to contribute directly or indirectly to future cash flows. Management will periodically assess the amortization period of intangible assets with definite lives based upon estimated future cash flows from related operations and tests for impairment when indicators arise.
Given the timing of the acquisition, no impairment indicators arose during the year ended ended December 31, 2013 which would give reason for an interim test to be performed on goodwill or intangible assets.
Revenue Recognition
The Company’s revenue is generated from sales of its products. Sales are recognized when the product is shipped and legal title has passed to the customer. The Company does not generate sales from arrangements with multiple deliverables.
Advertising and Promotional Materials
All advertising and promotional costs are expensed as incurred and amounted to approximately $0.4 million, $1.0 million and $1.2 million, in 2013, 2012 and 2011, respectively.
Repairs and Maintenance
Major renewals and improvements of property and equipment are capitalized, and repairs and maintenance are expensed as incurred. The Company incurred expenses relating to the repair and maintenance of plant and equipment of approximately $14.9 million, $13.8 million and $11.5 million, in 2013, 2012 and 2011, respectively.
Self-Insurance
The Company is self-insured for a portion of its risk on workers’ compensation and employee medical costs. The arrangements provide for stop loss insurance to manage the Company’s risk. Operations are charged with the cost of claims reported and an estimate of claims incurred but not reported based upon historical claims lag information and other data.
Product Warranty
The Company periodically incurs product warranty costs. Any liabilities associated with product warranty are estimated based on known facts and circumstances and are not significant at December 31, 2013, 2012 and 2011. The Company does not offer extended warranties on its products.
Income Taxes
The provision for income taxes is based on the earnings reported in the consolidated financial statements. Deferred income tax assets and liabilities are computed for differences between the financial statement and tax basis of assets and liabilities that will result in taxable or deductible amounts in the future. Such deferred income tax asset and liability computations are based on enacted tax laws and rates.
Earnings Per Share
The following table reconciles the numerators and denominators used in the calculations of basic and diluted earnings per share (EPS) for each of the last three years:
	2013		2012				2011
Numerators:
Numerator for both basic and diluted EPS, net income	$	222,929,949	$	168,586,840			$	164,668,228
Denominators:
Denominator for basic EPS, weighted-average common shares outstanding	143,460,018		143,097,530				142,492,699
Potentially dilutive shares resulting from stock option plans	814,153		870,501				1,784,109
Denominator for diluted EPS	144,274,171		143,968,031				144,276,808
For the years ended December 31, 2013, 2012 and 2011, 3,377,311, 3,332,719 and 1,253,824 shares, respectively, related to stock option plans were not included in diluted average common shares outstanding because their effect would be anti-dilutive.
Other Comprehensive Income (Loss)
Comprehensive income reflects the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. For the Company, comprehensive income represents net income adjusted for unrealized gains and losses on certain investments and foreign currency translation adjustments and is further detailed in Note 9 to the Consolidated Financial Statements.
Foreign Currency Translation
The financial position and results of operations of the Company’s foreign subsidiaries are measured using the local currency as the functional currency. Assets and liabilities are translated at the exchange rate in effect at year-end. Income statement accounts are translated at the average rate of exchange in effect during the year. The resulting translation adjustment is recorded as a separate component of shareholders’ investment. Gains and losses arising from re-measuring foreign currency transactions into the appropriate currency are included in the determination of net income.
Stock-Based Compensation Plans
The Company accounts for stock-based compensation using the fair value recognition provisions of ASC 718, “Share-Based Payment.” As described more fully in Note 5, the Company provides compensation benefits under two stock option plans, a restricted stock plan and an employee stock purchase plan.
Estimates
The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
New Accounting Standards
In February 2013, FASB issued Accounting Standards Update No. 2013-02, “Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income” (“ASU 2013-12”).  ASU 2013-02 requires an entity to report the effect of significant reclassifications out of accumulated other comprehensive income.  The amended guidance does not change the current requirements for reporting net income or other comprehensive income in financial statements.  However, the amended guidance requires an entity to provide information regarding the amounts reclassified out of accumulated other comprehensive income by component, either on the face of the statement where net income is presented or in the notes to the condensed consolidated financial statements.  The amended guidance was effective for financial periods beginning after December 15, 2012.  ASU 2013-02 did not have a material effect on the Company's consolidated financial position or results of operations. Refer to Note 9, "Comprehensive Income," of the notes to consolidated financial statements for disclosures regarding other comprehensive income.

Debt_and_Financing_Arrangement

Debt and Financing Arrangements	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Debt and Financing Arrangements	'
	On September 27, 2013, the Company entered into a Credit Agreement (the “Credit Agreement”) with certain banks and agents.
	Pursuant to the Credit Agreement, the Company is borrower under a $150 million senior revolving credit facility (the “Revolving Facility”) and a $150 million term loan facility (the “Term Loan”). Under the terms of the Credit Agreement, the Company is entitled, subject to the satisfaction of certain conditions, to further request an additional aggregate principal amount of up to $75 million. In addition, the Company is entitled, subject to certain terms and conditions, to the benefit of swing loans from amounts otherwise available under the Revolving Facility in the aggregate principal amount of up to $20 million and to request Letters of Credit from amounts otherwise available under the Revolving Facility in the aggregate principal amount of up to $20 million. The obligations of the Company under the Credit agreement are not secured, but are subject to certain covenants .
	The interest rates per annum applicable to loans, other than swing loans, under the Credit Agreement will be, at the Company’s option and subject to certain conditions, equal to either a base rate or a LIBOR rate for one, two, three or six-month interest periods chosen by the Company, plus an applicable margin percentage. The base rate will be the highest of (i) the federal funds rate plus 0.50%, (ii) the agent’s prime rate or (iii) the LIBOR rate plus 1.00%. The LIBOR rate will be equal to the London interbank offered rates for U.S. Dollars quoted by Bloomberg or the appropriate successor, divided by a number equal to 1 minus the maximum percentage in effect on such day for determining reserve requirements, as prescribed by the Board of Governors of the Federal Reserve System. The applicable margin percentage is based on the leverage ratio of the Company. The range of the applicable margin percentage is 1.00% per annum to 1.75% per annum in the case of the LIBOR rate and 0.00% per annum to 0.75% per annum in the case of the base rate.
	The Credit Agreement contains customary representations and warranties and certain covenants that limit the ability of the Company and certain of its subsidiaries to, among other things: (i) incur or guarantee additional indebtedness; (ii) redeem or repurchase subordinated debt; (iii) sell or otherwise transfer or dispose of certain assets; (iv) make certain investments; (v) incur or suffer to exists liens securing indebtedness; (vi) dissolve, liquidate, consolidate, merge or wind-up its affairs; (vii) engage in certain transactions with affiliates; or (viii) make certain other negative pledges. In addition, the Credit Agreement contains financial covenants that limit capital expenditures in any fiscal year and that measure (i) the ratio of the Company’s total funded indebtedness net of certain cash to the amount of the Company’s consolidated Earnings Before Interest, Taxes, Depreciation and Amortization ("EBITDA") and (ii) the ratio of the amount of the Company’s consolidated EBITDA to the Company’s cash interest expense. The Credit Agreement also includes customary events of default.
	The Revolving Facility expires and the Term Loan matures on September 27, 2018.
	In connection with the HomeLink® acquisition which was completed on September 27, 2013, which is discussed in Note 10, the Company borrowed $275 million related to the Credit Agreement, composed of $125 million under the revolving facility and $150 million on the term loan. During the quarter ended December 31, 2013, the Company made a partial repayment of $1.9 million, plus accrued interest, on the Term Loan, and accrued interest on the Revolving facility. The Company used cash and cash equivalents to fund the payment. As of December 31, 2013, the Company had availability of $26.9 million under the Credit Agreement (exclusive of additional aggregate principal amounts which can be requested as discussed above).
	Cash paid for interest expenses for twelve months ended December 31, 2013, which were netted within the "Other, net" section of the income statement were $0.9 million. There was no cash paid for interest expenses for the years ended December 31, 2012 and 2011.
	As of December 31, 2013, the Company was in compliance with its covenants under the Credit Agreement.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	INCOME TAXES
	The Company follows the provisions of the Financial Accounting Standards Codification 740 (“ASC 740”), “Accounting for Uncertainty in Income Taxes.” A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:
		2013				2012				2011
	Beginning of year	$	4,168,000			$	2,476,000			$	2,483,000
	Additions based on tax positions related to the current year	1,595,000				785,000				1,105,000
	Additions for tax positions in prior years	1,633,000				907,000				208,000
	Reductions for tax positions in prior years	(45,000		)		—				(78,000		)
	Reductions as a result of completed audit examinations	—				—				(1,242,000		)
	End of year	$	7,351,000			$	4,168,000			$	2,476,000
	If recognized, unrecognized tax benefits would affect the effective tax rate.
	The Company recognizes interest and penalties related to unrecognized tax benefits through the provision for income taxes. The Company has accrued approximately $555,000 and $250,000 for interest as of December 31, 2013 and 2012, respectively. Interest recorded during 2013, 2012 and 2011 was not considered significant.
	The Company is also subject to periodic and routine audits in both domestic and foreign tax jurisdictions, and it is reasonably possible that the amounts of unrecognized tax benefits could change as a result of an audit. Based on the current audits in process, the payment of taxes as a result of audit settlements and the completion of tax examinations are not expected to have a material impact on the Company’s financial position or results of operations.
	For the majority of tax jurisdictions, the Company is no longer subject to U.S. federal, state and local, or non-U.S. income tax examinations by tax authorities for years before 2009.
	In May 2011, the State of Michigan enacted a new Corporate Income Tax that was effective January 1, 2012. The new Corporate Income Tax does not have a significant effect on the Company’s consolidated financial position or results of operations.
	In January 2013, the American Taxpayer Relief Act of 2012 was signed into law and reinstated retroactively to January 1, 2012 various tax provisions known as tax "extenders" that had expired as of December 31, 2011. In accordance with ASC 740-45-15, the effects of changes in tax rates and laws on deferred tax balances and tax rates are recognized in the period the new legislation is enacted. As a result, the impact of the new legislation is reflected in the Company's consolidated financial position and results of operations in calendar year 2013.
	The provision for income taxes is based on the earnings reported in the accompanying consolidated financial statements. The Company recognizes deferred income tax liabilities and assets for the expected future tax consequences of events that have been included in the consolidated financial statements or tax returns. Under this method, deferred income tax liabilities and assets are determined based on the cumulative temporary differences between the financial statement and tax bases of assets and liabilities using enacted tax rates. Deferred income tax expense is measured by the net change in deferred income tax assets and liabilities during the year.
	The foreign components of income before the provision for income taxes were not material as of December 31, 2013, 2012 and 2011. The components of the provision for income taxes are as follows:
		2013				2012				2011
	Currently payable:
	Federal	$	95,285,094			$	76,507,760			$	63,307,583
	State	3,259,000				2,450,000				1,663,000
	Foreign	1,353,000				1,238,000				850,000
	Total	99,897,094				80,195,760				65,820,583
	Net deferred:
	Primarily federal	5,237,000				843,000				13,943,000
	Provision for income taxes	$	105,134,094			$	81,038,760			$	79,763,583
	The currently payable provision is further reduced by the tax benefits associated with the exercise, vesting or disposition of stock under the stock plans described in Note 5. These reductions totaled approximately $7.4 million, $1.5 million and $7.9 million in 2013, 2012 and 2011, respectively, and were recognized as an adjustment of additional paid-in capital.
	The effective income tax rates are different from the statutory federal income tax rates for the following reasons:
		2013			2012			2011
	Statutory federal income tax rate	35	%		35	%		35	%
	State income taxes, net of federal income tax benefit	0.6			0.6			0.1
	Domestic production exclusion	(3.1	)		(2.9	)		(2.3	)
	Research tax credit	(0.4	)		—			—
	Other	(0.1	)		(0.2	)		(0.2	)
	Effective income tax rate	32	%		32.5	%		32.6	%
	The tax effect of temporary differences which give rise to deferred income tax assets and liabilities at December 31, 2013 and 2012, are as follows:
		2013								2012
		Current				Non-Current				Current			Non-Current
	Assets:
	Accruals not currently deductible	$	2,970,671			$	182,803			$	3,721,183		$	186,997
	Stock based compensation	13,290,429				2,202,940				12,044,953			1,696,966
	Impairment loss on available-for-sale securities	—				175,091				—			327,308
	Intangible Assets	—				169,913				—			—
	Other	4,713,241				40,203				5,690,130			3,609
	Total deferred income tax assets	20,974,341				2,770,950				21,456,266			2,214,880
	Liabilities:
	Excess tax over book depreciation	—				(41,374,851		)		—			(47,704,521		)
	Patent costs	—				(1,792,968		)		—			(8,137,111		)
	Unrealized gain on investments	—				(10,482,468		)		—			(3,146,585		)
	Other	(558,249		)						(527,417		)	—
	Net deferred income taxes	$	20,416,092			$	(50,879,337	)		$	20,928,849		$	(56,773,337	)
	Income taxes paid in cash were approximately $97.1 million, $63.4 million and $63.5 million in 2013, 2012 and 2011, respectively.
	No provision has been made for U.S. Federal and State income taxes on foreign taxes that may result from remittances of undistributed earnings of foreign subsidiaries as of December 31, 2013, 2012 and 2011.
	The Company expects such earnings will remain reinvested in those foreign subsidiaries indefinitely. Undistributed foreign earnings were not material as of December 31, 2013, 2012 and 2011.

Employee_Benefit_Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]	'
Employee Benefit Plan	'
	EMPLOYEE BENEFIT PLAN
	The Company has a 401(k) retirement savings plan in which substantially all of its employees may participate. The plan includes a provision for the Company to match a percentage of the employee’s contributions at a rate determined by the Company’s Board of Directors. In 2013, 2012 and 2011 the Company’s contributions were approximately $2.8 million, $2.5 million and $2.3 million, respectively.
	The Company does not provide health care benefits to retired employees.

StockBased_Compensation_Plans

Stock-Based Compensation Plans	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stock-Based Compensation Plans	'
	STOCK-BASED COMPENSATION PLANS
	Employee Stock Option Plan
	In 2004, a new Employee Stock Option Plan was approved by shareholders, replacing the prior plan. The Company may grant options for up to 18,000,000 shares under its new Employee Stock Option Plan. The Company has granted options on 15,723,739 shares (net of shares from canceled/expired options) under the new plan through December 31, 2013. Under the plans, the option exercise price equals the stock’s market price on date of grant. The options vest after one to five years, and expire after three to seven years.
	The fair value of each option grant in the Employee Stock Option Plan was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions for the indicated periods:
		2013				2012				2011
	Dividend yield (1)	2.6		%		2.7		%		2.7		%
	Expected volatility (2)	44.7		%		45.5		%		41.6		%
	Risk-free interest rate (3)	1.3		%		0.8		%		1.4		%
	Expected term of options (in years) (4)	4				4.1				4.2
	Weighted-average grant-date fair value	$	7			$	6			$	8
	(1)    Represents the Company's estimated cash dividend yield over the expected term of option grant.
	-2	Amount is determined based on analysis of historical price volatility of the Company's common stock. The expected volatility is based on the daily percentage change in the price of the stock over a period equal to the expected term of the option grant.
	(3)    Represents the U.S. Treasury yield over the expected term of the option grant.
	-4	Represents the period of time that options granted are expected to be outstanding. Based on analysis of historical option exercise activity, the Company has determined that all employee groups exhibit similar exercise and post-vesting termination behavior.
	As of December 31, 2013, there was $24,527,192 of unrecognized compensation cost related to share-based payments which is expected to be recognized over the remaining vesting periods, with a weighted-average period of 2.2 years.
	A summary of the status of the Company’s employee stock option plan at December 31, 2013, 2012 and 2011, and changes during the same periods are presented in the tables and narrative below:
		2013
		Shares			Wtd. Avg.				Wtd. Avg.		Aggregate
		0			Ex. Price				Remaining		Intrinsic
									Contract Life		Value
											0
	Outstanding at Beginning of Year	8,861			$	21
	Granted	2,731			25
	Exercised	(2,225	)		16						$	20,884
	Forfeited	(367	)		23
	Outstanding at End of Year	9,000			23				3.4 Yrs		$	85,633
	Exercisable at End of Year	2,745			$	23			2.3 Yrs		$	28,302
		2012
		Shares			Wtd. Avg.				Wtd. Avg.		Aggregate
		0			Ex. Price				Remaining		Intrinsic
									Contract Life		Value
											0
	Outstanding at Beginning of Year	7,555			$	21
	Granted	2,641			20
	Exercised	(689	)		15						$	3,810
	Forfeited	(646	)		21
	Outstanding at End of Year	8,861			21				3.4 Yrs		$	11,730
	Exercisable at End of Year	3,003			$	19			2.2 Yrs		$	7,617
		2011
		Shares			Wtd. Avg.				Wtd. Avg.		Aggregate
		0			Ex. Price				Remaining		Intrinsic
									Contract Life		Value
											0
	Outstanding at Beginning of Year	6,805			$	17
	Granted	2,462			29
	Exercised	(1,497	)		16						$	20,659
	Forfeited	(215	)		19
	Outstanding at End of Year	7,555			21				3.5 Yrs		$	66,295
	Exercisable at End of Year	2,024			$	17			2.3 Yrs		$	26,218
	A summary of the status of the Company’s non-vested employee stock option activity for the years ended December 31, 2013, 2012, and 2011, are presented in the table and narrative below:
		2013							2012					2011
		Shares			Wtd. Avg				Shares			Wtd. Avg		Shares		Wtd. Avg
		0			Grant				0			Grant		0		Grant
					Date							Date				Date
					Fair Value							Fair Value				Fair Value
	Nonvested Stock Options at Beginning of Year	5,858			$	6			5,530			$	6	5,038		$	5
	Granted	2,731			7				2,641			6		2,462		8
	Vested	(2,022	)		6				(1,936	)		5		(1,766	)	5
	Forfeited	(313	)		7				(377	)		6		(204	)	5
	Nonvested Stock Options at End of Year	6,254			$	7			5,858			$	6	5,530		$	6
	Non-employee Director Stock Option Plan
	In 2012, an Amended and Restated Non-employee Director Stock Option Plan, covering a total of 500,000 shares of common stock, was approved by shareholders replacing a prior plan. The Company has granted options on 84,000 shares (net of shares from canceled options) under the new director plan and 549,240 shares (net of shares from canceled options) under a prior plan through December 31, 2013. Under the shareholder approved plans, the option exercise price equals the stock's market price on date of grant. The options vest after six months, and expire after ten years.
	The fair value of each option grant in the Non-employee Director Stock Option Plans was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions for the indicated periods:
	2013				2012				2011
Dividend yield (1)	2.7		%		2.6		%		2.7		%
Expected volatility (2)	45.9		%		44.5		%		40.5		%
Risk-free interest rate (3)	1.9		%		1.7		%		3.2		%
Expected term of options (in years) (4)	7				6.8				6.5
Weighted-average grant-date fair value	$	9			$	8			$	11
(1)    Represents the Company's estimated cash dividend yield over the expected term of option grant.
-2	Amount is determined based on analysis of historical price volatility of the Company's common stock. The expected volatility is based on the daily percentage change in the price of the stock over a period equal to the expected term of the option grant.
(3)    Represents the U.S. Treasury yield over the expected term of the option grant.
-4	Represents the period of time that options granted are expected to be outstanding. Based on analysis of historical option exercise activity, the Company has determined that non-employee directors exhibit similar exercise and post-vesting termination behavior.
As of December 31, 2013, there was no unrecognized compensation cost related to share-based payments under this plan.
A summary of the status of the Company’s Non-employee Director Stock Option Plan at December 31, 2013, 2012, and 2011, and changes during the same periods are presented in the tables and narrative below:
	2013
	Shares			Wtd. Avg.				Wtd. Avg.		Aggregate
	0			Ex. Price				Remaining		Intrinsic
								Contract Life		Value
										0
Outstanding at Beginning of Year	234			$	21
Granted	42			25
Exercised	(45	)		20						$	300
Forfeited	—			—
Outstanding at End of Year	231			22				6.4 Yrs		$	2,491
Exercisable at End of Year	231			$	22			6.4 Yrs		$	2,491
	2012
	Shares			Wtd. Avg.				Wtd. Avg.		Aggregate
	0			Ex. Price				Remaining		Intrinsic
								Contract Life		Value
										0
Outstanding at Beginning of Year	192			$	21
Granted	42			22
Exercised	—			—
Forfeited	—			—
Outstanding at End of Year	234			21				6.4 Yrs		$	225
Exercisable at End of Year	234			$	21			6.4 Yrs		$	225
	2011
	Shares			Wtd. Avg.				Wtd. Avg.		Aggregate
	0			Ex. Price				Remaining		Intrinsic
								Contract Life		Value
										0
Outstanding at Beginning of Year	244			$	18
Granted	42			32
Exercised	(94	)		17						$	1,362
Forfeited	—			—
Outstanding at End of Year	192			21				6.8 Yrs		$	1,740
Exercisable at End of Year	192			$	21			6.8 Yrs		$	1,740
A summary of the status of the Company’s non-vested Non-employee Director Stock Option Plan activity for the years ended December 31, 2013, 2012, and 2010, are presented in the table and narrative below:
	2013							2012					2011
	Shares			Wtd. Avg				Shares			Wtd. Avg		Shares		Wtd. Avg
	0			Grant Date				0			Grant Date		0		Grant Date
				Fair Value							Fair Value				Fair Value
Nonvested stock options at Beginning of Year	—			$	—			—			$	—	—		$	—
Granted	42			9				42			8		42		11
Vested	(42	)		9				(42	)		8		(42	)	11
Forfeited								—			—		—		—
Nonvested stock options at End of Year	—			$	—			—			$	—	—		$	—
Employee Stock Purchase Plan
In May 2013, the 2013 Gentex Corporation Employee Stock Purchase Plan covering 1,000,000 shares of common stock was approved by the shareholders, replacing a prior plan. Under such plan, the Company sells shares at 85% of the stock’s market price at date of purchase. Under ASC 718, the 15% discounted value is recognized as compensation expense. The following table summarizes shares sold to employees under the 2013 Plan and the prior plan in the years ended December 31, 2013, 2012 and 2011.
Plan	2013			2012			2011		Cumulative Shares Issued in 2013		Weighted Average Fair Value 2013
2013 Employee Stock Purchase Plan	51,462			—			—		51,462		$	22.64
2003 Employee Stock Purchase Plan	26,170			102,498			68,630		1,200,000		$	17.01
Total shares sold to employees	77,632			102,498			68,630
Restricted Stock Plan
In 2008, an amendment to the Company’s Second Restricted Stock Plan was approved by shareholders. The Plan amendment increased the maximum number of shares that may be subject to awards to 2,000,000 shares and to extend the Plan’s termination date to February 21, 2018. The purpose of this plan is to permit grants of shares, subject to restrictions, to key employees of the Company as a means of retaining and rewarding them for long-term performance and to increase their ownership in the Company. Shares awarded under the plan entitle the shareholder to all rights of common stock ownership except that the shares may not be sold, transferred, pledged, exchanged or otherwise disposed of during the restriction period. The restriction period is determined by a committee, appointed by the Board of Directors, but may not exceed ten years. The Company has 768,200 shares outstanding under the plan as of December 31, 2013. During 2013, 2012, and 2011, 187,090, 225,730 and 140,900 shares, respectively, were granted with a restriction period of five years at market prices ranging from $20.23 to $32.83 in 2013, $17.27 to $24.45 in 2012, and $24.96 to $30.25 in 2011, and has unearned stock-based compensation of $9,762,379 associated with these restricted stock grants. The unearned stock-based compensation related to these grants is being amortized to compensation expense over the applicable restriction periods. Amortization expense of restricted stock for years ended December 31, 2013, 2012 and 2011 was $2,760,446, $2,108,583. and 2,039,377 respectively.

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Contingencies	'
	CONTINGENCIES
	On June 25, 2012, American Vehicular Sciences LLC (“AVS”) filed four patent infringement complaints in the United States District Court in the Eastern District of Texas, which named the Company and one of two of its customers as co-defendants. In two of the complaints (#6:12-cv-00413 and #6:12-cv-00406), AVS alleged that the Company's SmartBeam® product infringed one patent owned by AVS. In the other two complaints (#6:12-cv-00410 and #6:12-cv-00415), AVS alleged that the Company's monitoring system products infringe two other patents owned by AVS. The Company was served with the four complaints on July 27, 2012. On October 5, 2012, the Company submitted its answers to all four complaints.
	On December 28, 2012, in the ordinary course of business, the Company entered into a settlement/license agreement (“agreement”) with AVS, settling all pending litigation. The cost associated with the agreement was accrued by the Company and reflected in its financial results as of December 31, 2012. As a result of the agreement, the United States District Court in the Eastern District of Texas has ordered that the Company is dismissed with prejudice as a defendant in the complaints filed by AVS.
	The Company is periodically involved in legal proceedings, legal actions and claims arising in the normal course of business, including proceedings relating to product liability, intellectual property, safety and health, employment and other matters. Such matters are subject to many uncertainties and outcomes are not predictable. The Company does not believe, however, that at the current time any of these matters constitute material pending legal proceedings that will have a material adverse effect on the financial position or future results of operations of the Company.

Segment_Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Segment Reporting	'
	SEGMENT REPORTING
	ASC 280, “Disclosures About Segments of an Enterprise and Related Information,” requires that a public enterprise report financial and descriptive information about its reportable operating segments subject to certain aggregation criteria and quantitative thresholds. Operating segments are defined by ASC 280 as components of an enterprise about which separate financial information is available that is evaluated regularly by the chief operating decision-makers in deciding how to allocate resources and in assessing performance.
		2013				2012			2011
	Revenue:
	Automotive Products
	United States	$	400,654,021			$	382,308,501		$	334,692,637
	Germany	244,949,664				239,081,723			248,495,295
	Japan	123,884,470				100,422,507			76,123,221
	Other	374,499,972				355,160,210			343,850,209
	Other	27,876,044				22,586,580			20,600,687
	Total	$	1,171,864,171			$	1,099,559,521		$	1,023,762,049
	Income (Loss) from Operations:
	Automotive Products	$	298,465,299			$	231,713,972		$	231,030,145
	Other	6,276,514				2,741,260			337,780
	Total	$	304,741,813			$	234,455,232		$	231,367,925
	Assets:
	Automotive Products	$	1,290,801,674			$	619,337,527		$	566,395,900
	Other	9,001,278				8,010,779			8,993,853
	Corporate	464,285,482				638,343,029			600,637,249
	Total	$	1,764,088,434			$	1,265,691,335		$	1,176,027,002
	Depreciation & Amortization:
	Automotive Products	$	58,723,222			$	47,976,800		$	40,314,620
	Other	316,836				317,534			320,900
	Corporate	3,814,097				1,885,489			1,999,164
	Total	$	62,854,155			$	50,179,823		$	42,634,684
	Capital Expenditures:
	Automotive Products	$	54,020,792			$	113,611,526		$	115,377,859
	Other	301,697				228,635			58,996
	Corporate	1,057,968				3,634,288			4,740,875
	Total	$	55,380,457			$	117,474,449		$	120,177,730
	Other includes Fire Protection Products and Dimmable Aircraft Windows. Dimmable Aircraft Window net sales continued to increase during 2011, 2012 and 2013, which resulted in income from operations for each of the three years presented in the “Other” category.
	Corporate assets are principally cash and cash equivalents, investments, deferred income taxes and corporate fixed assets. Substantially all long-lived assets are located in the U.S.
	Automotive Products revenues in the “Other” category are sales to customer automotive manufacturing plants in Korea, Mexico, Canada, Hungary, China, and the United Kingdom as well as other foreign automotive customers. Most of the Company’s non-U.S. sales are invoiced and paid in U.S. dollars. During the years ended December 31, 2013, 2012 and 2011, approximately 7% , 8% and 9% of the Company’s net sales were invoiced and paid in foreign currencies respectively.
	In 2013, the Company had three automotive customers (includes direct sales to OEM customers and sales through their Tier 1 suppliers), which individually accounted for 10% or more of net sales as follows:
		Toyota Motor Corporation		VW/Audi			Hyundai/Kia		Daimler AG		General Motors
	2013	13	%	14	%		#		11	%	#
	2012	14	%	14	%		11	%	11	%	10	%
	2011	12	%	15	%		11	%	11	%	12	%
	# - Less than 10 percent.

Quarterly_Financial_Informatio

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Quarterly Financial Information (Unaudited)	'
	QUARTERLY FINANCIAL INFORMATION (UNAUDITED)
	The following table sets forth selected financial information for all of the quarters during the years ended December 31, 2013 and 2012 (in thousands, except per share data):
		First				Second				Third				Fourth
		2013		2012		2013		2012		2013		2012		2013		2012
	Net Sales	$	269,499	$	290,707	$	286,974	$	280,256	$	288,622	$	268,248	$	326,770	$	260,349
	Gross Profit	93,464		100,826		102,613		92,757		105,962		90,116		128,694		89,119
	Operating Income	63,854		65,501		71,596		57,512		73,656		57,623		95,636		53,819
	Net Income	45,431		46,345		52,097		40,767		55,521		41,877		69,881		39,599
	Earnings Per Share (Diluted)	$	0.32	$	0.32	$	0.36	$	0.28	$	0.38	$	0.29	$	0.48	$	0.28
	Earnings Per Share (Basic)	$	0.32	$	0.32	$	0.36	$	0.28	$	0.39	$	0.29	$	0.48	$	0.28

Comprehensive_Income

Comprehensive Income	12 Months Ended
	Dec. 31, 2013
Comprehensive Income [Abstract]	'
Comprehensive Income	'
	Comprehensive Income
	Comprehensive income reflects the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. For the Company, comprehensive income represents net income adjusted for unrealized gains and losses on certain investments and foreign currency translation adjustments.
		For the Twelve Months ended December 31,
		2013				2012				2011
	Foreign currency translation adjustments:
	Balance at beginning of period	$	2,458,933			$	2,129,957			$	566,903
	Other Comprehensive income before reclassifications	48,989				328,976				1,563,054
	Amounts reclassified from accumulated other comprehensive income	—				—				—
	Net current-period change	48,989				328,976				1,563,054
	Balance at end of period	2,507,922				2,458,933				2,129,957
	Unrealized gains(losses) on available-for-sale securities:
	Balance at beginning of period	15,111,778				10,412,246				21,750,000
	Other Comprehensive income before reclassifications	16,139,845				10,138,902				(7,012,974		)
	Amounts reclassified from accumulated other comprehensive income	(11,784,182		)		(5,439,370		)		(4,324,780		)
	Net current-period change	4,355,663				4,699,532				(11,337,754		)
	Balance at end of period	19,467,441				15,111,778				10,412,246
	Accumulated other comprehensive income, end of period	$	21,975,363			$	17,570,711			$	12,542,203
	All amounts are shown net of tax. Amounts in parentheses indicate debits.
	The following table presents details of reclassifications out of other comprehensive income for the twelve months ended December 31, 2013, 2012 and 2011.
	Details about Accumulated Other Comprehensive Income Components		Amounts Reclassified from Other Comprehensive Income											Affected Line item in the Statement of Consolidated Income
			For the Twelve Months ended December 31,
			2013				2012				2011
	Unrealized gains and (losses) on available-for-sale securities
	Realized gain (loss) on sale of securities		$	18,129,511			$	8,368,261			$	6,653,508		Other, net
	Provision for Income Taxes		(6,345,329		)		(2,928,891		)		(2,328,728		)	Provision for Income Taxes
	Total reclassifications for the period		$	11,784,182			$	5,439,370			$	4,324,780		Net of tax

Business_Combinations

Business Combinations	12 Months Ended
	Dec. 31, 2013
Business Combinations [Abstract]	'
Business Combinations	'
	On September 27, 2013, the Company completed the acquisition of certain assets and liabilities of Johnson Controls, Inc. (the “Seller”) related to the Seller’s wireless vehicle/home communication HomeLink® business. Prior to the above-described acquisition, the Seller supplied HomeLink® products and was a licensor of HomeLink® to the Company, which allowed for incorporation into the Company’s rearview mirror products, that are installed in automobiles. The aggregate purchase price for the Business paid at the closing was approximately $700 million, subject to adjustments as provided in the Asset Purchase Agreement.
	The HomeLink® acquisition was done to secure the Company’s current customers and product offerings in HomeLink® mirrors and to enable and expand its capabilities beyond the mirror. Even prior to the acquisition the Company offered HomeLink® mirrors as part of its existing product portfolio. HomeLink® mirror products have been sold by the Company in the marketplace for over 10 years, where the Company was previously a licensee of the technology. After the acquisition, there are certain synergies the Company hopes to capitalize upon. There is significant value in the HomeLink® brand, including consumer awareness when shopping for new automobiles equipped with the feature. The acquisition enables the Company to continue its long history of development and growth of the HomeLink® mirror based products, as well as to add HomeLink® products that are not based in the mirror. The Company believes it will be able to apply its expertise in electronics manufacturing to enhance even further the quality and reliability of the HomeLink® products.
	The assets acquired and liabilities assumed were recorded at fair value on the acquisition date. The Company accounted for the acquisition under the provisions of FASB ASC Topic 805, Business Combinations. Revenues related to the Business, of thirty-six million nine hundred thousand and gross profit of twenty million two hundred thousand, for the quarter and year to date period ended December 31, 2013, are included in the Company’s consolidated statement of income and comprehensive income since the acquisition date. The operating results for the Business are included in the Automotive Products segment, consistent with the Company's treatment of other features.
	Separate from the Asset Purchase Agreement, the Seller and the Company have entered into a Supply Agreement, in the ordinary course of business, whereby the Company agrees to supply HomeLink® product to the Seller for incorporation into the Seller’s vehicular products. The Supply Agreement contains customary terms and conditions which are consistent with market rates for sales of similar products to other parties. Due to the nature of the Supply Agreement and the fact that terms are at arms length, there has not been a portion of the purchase price which has been allocated to the Supply Agreement.
	The Company funded the transaction using a combination of cash on hand of approximately $423 million and debt financing. The Company’s debt financing included net proceeds from the Company’s new Credit Agreement as described in Note 2.
	Through December 31, 2013, the Company has incurred acquisition-related costs of approximately $3.3 million of which approximately $2.3 million has been expensed as incurred in the "Selling, general & administrative" section of its Condensed Consolidated Income Statement. The remaining costs of approximately $1.0 million, were related to the issuance of the Company's new debt financing, further explained in Note 2, which has been classified in the "Prepaid Expenses and Other" section of its' Condensed Consolidated Balance Sheet and will be amortized over the life of the credit agreement.
	The below table shows the preliminary allocation of the purchase price as of September 30, 2013 and subsequent adjustments to the preliminary allocation as of December 31, 2013.
	Net Assets Acquired	Fair Value as of September 30, 2013		Fair Value Adjustments			Other Adj			Fair Value as of December 31, 2013
	Prepaid Service Agreement Costs (1)	$	3,383,000	$	—		$	(3,383,000	)	$	—
	Personal Property	4,430,986		3,683,614			—			8,114,600
	Real Property	1,060,000		—			—			1,060,000
	HomeLink® Trade Names and Trademarks	47,000,000		5,000,000			—			52,000,000
	HomeLink®Technology	166,000,000		14,000,000			—			180,000,000
	Existing Customer Platforms	43,000,000		—			—			43,000,000
	Exclusive Licensing Agreement	87,000,000		9,000,000			—			96,000,000
	Accounts Receivable	7,719,302		—			3,400,145			11,119,447
	Net Customer Tooling	956,665		—			26,741			983,406
	Fair Value of Acquired Assets	360,549,953		31,683,614			43,886			392,277,453
	Other adjustments	—		—			(1,492,398		)	(1,492,398		)
	Goodwill	337,557,061		(31,683,614		)	1,492,398			307,365,845
	Total Cash Consideration	$	698,107,014	$	—		$	43,886		$	698,150,900
	(1) - The Company used the prepaid service agreement costs to offset payments due to the Seller in the quarter ended , December 31, 2013.
	The following unaudited pro forma condensed consolidated statement of income for twelve month periods ended December 31, and 2012 include pro-forma adjustments to reflect the effect of the acquisition as if it had occurred on January 1, 2013. This unaudited pro forma consolidated statement of income is provided for informational purposes only and does not purport to be indicative of the results which would have actually been attained had the acquisition occurred on January 1, 2013 or that may be attained in the future.
	PRO FORMA CONDENSED CONSOLIDATED STATEMENT OF INCOME
	Twelve Months Ended December 31,
		2013		2012
	Net Sales	$	1,271,320	$	1,216,009
	Net Income	253,678		205,023
	Managements preliminarily allocation of fair values to the identifiable intangible assets was completed through a combination of the relief from royalty and the excess earnings methods.The allocation of the purchase price above is considered preliminary and was based upon valuation information available and estimates and assumptions made as of December 31, 2013. Throughout the fourth quarter of 2013 the Company has worked with valuation specialists in verifying data and information related to the valuation and recording of identifiable intangible assets, net working capital,and the resulting effects on the amount of recorded goodwill. The Company expects to finalize these matters within the measurement period, which is currently expected to remain open through the first quarter of 2014.

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill and Other Intangible Assets	'
	Goodwill represents the cost of an acquisition in excess of the fair values assigned to identifiable net assets acquired. On September 27, 2013, the Company recorded Goodwill of $337.6 million detailed further in Note 10. As of December 31, 2013, the Company adjusted recorded Goodwill to $307.4 million resulting from refinement of the purchase accounting estimates, based on updated valuations of tangible and intangible assets acquired as part of the HomeLink® acquisition. The amount of Goodwill that is expected to be deductible for tax purposes is $307.4 million. The following table shows the carrying value of Goodwill as of December 31, 2012 and December 31, 2013.
		Carrying Amount
	Balance as of December 31, 2012	$	—
	Acquisitions	307,365,845
	Divestitures	—
	Impairments	—
	Other	—
	Balance as of December 31, 2013	$	307,365,845
	The Intangible assets and related change in carrying values are shown below as of December 31, 2013. Please see Note 10 for a reconciliation of preliminary asset valuations as of September 30, 2013 and related adjustments to intangible asset values as of December 31, 2013:
	Other Intangible Assets	Gross		Accumulated Amortization			Net		Assumed Useful Life
	HomeLink®Trade Names and Trademarks	$	52,000,000	$	—		$	52,000,000	Indefinite
	HomeLink® Technology	180,000,000		(3,750,000		)	$	176,250,000	12 years
	Existing Customer Platforms	43,000,000		(1,075,000		)	$	41,925,000	10 years
	Exclusive Licensing Agreement	96,000,000		—			$	96,000,000	Indefinite
	Total other identifiable intangible assets	$	371,000,000	$	(4,825,000	)	$	366,175,000
	The HomeLink® Trade Name and Trademarks were valued utilizing the relief from royalty valuation method, which is a function of projected revenue, the royalty rate that would hypothetically be charged by a licensor of an asset to an unrelated licensee discounted utilizing market participants weighted average cost of capital. The royalty rate utilized in the analysis was a combination of the historical royalty rate that was paid by the Company to the Seller for the right to use the HomeLink® name in the market and the manufacturing of products using HomeLink® propietary technology, as well as other market transactions within the industry. Further, the royalty rate made considerations for factors such as age, market competition, absolute and relative profitability, market share and prevailing rates from similar assets. The discount rate applied was based on the weighted average cost of capital.
	The HomeLink® Technology and the Existing Customer Platform assets were valued using forms of the multi-period excess earnings valuation method which estimates future revenues and cash flows derived from the technology, and then subsequently deducts portions of future cash flow that is supported by other intangibles and fixed assets. The resulting cash flows are discounted using a weighted average cost of capital.
	The Exclusive Licensing Agreement asset was valued based on a "with or without" valuation methodology. This method compares the Company's estimated future cash flow projections with the exclusive agreement compared to those same cash flows without that exclusive license agreement.
	As the valuation methodologies for the aforementioned intangible assets utilize unobservable inputs, the Company considers the estimated fair value of the assets to be a level 3 measurement in the fair value hierarchy.
	The identified intangible asset lives range from 10 years to indefinite. Accumulated amortization on patents and intangible assets was approximately $13.4 million and $6.1 million at December 31, 2013 and 2012, respectively. At December 31, 2013, patents had a weighted average amortization life of 11 years. Amortization expense was approximately $7.9 million, $1.7 million, and $1.1 million in 2013, 2012 and 2011, respectively. Excluding the impact of any future acquisitions and any subsequent changes to the updated purchase price allocation, the Company anticipates amortization expense for each of the years ended December 31, 2014, 2015, 2016, 2017 and 2018 to be approximately $22 million annually.

Summary_of_Significant_Account1

Summary of Significant Accounting and Reporting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Consolidation	'
	Consolidation
	The consolidated financial statements include the accounts of Gentex Corporation and all of its wholly-owned subsidiaries (together the “Company”). All significant intercompany accounts and transactions have been eliminated.
Cash Equivalents	'
	Cash Equivalents
	Cash equivalents consist of funds invested in bank accounts and money market funds that have daily liquidity.
Allowance For Doubtful Accounts	'
	Allowance For Doubtful Accounts
	The Company bases its allowances for doubtful accounts related to receivables on historical credit and collections experience, and the specific identification of other potential problems, including the economic climate. Actual collections can differ, requiring adjustments to the allowances. Individual accounts receivable balances are evaluated on a monthly basis, and those balances considered uncollectible are charged to the allowance. Collections of amounts previously written off are recorded as an increase to the allowance.
	The following table presents the activity in the Company’s allowance for doubtful accounts:
		Beginning		Net				Deductions				Ending
		Balance		Additions/				and Other				Balance
				(Reductions)				Adjustments
				to Costs and
				Expenses
	Year Ended December 31, 2013:
	Allowance for Doubtful Accounts	$	3,400,000	$	—			$	197,612			$	3,202,388
	Year Ended December 31, 2012:
	Allowance for Doubtful Accounts	$	3,400,000	$	(577	)		577*				$	3,400,000
	Year Ended December 31, 2011:
	Allowance for Doubtful Accounts	$	4,300,000	$	(802,929	)		$	(97,071	)*		$	3,400,000
	*Represents excess recoveries and other adjustments over accounts written off.
	The Company’s overall allowance for doubtful accounts primarily relates to financially distressed Tier 1 automotive customers. The Company continues to work with these financially distressed customers in collecting past due balances.
Investments	'
	Investments
	The Company follows the provisions of ASC 820, “Fair Value Measurements and Disclosures” for its financial assets and liabilities, and for its non-financial assets and liabilities subject to fair value measurements. ASC 820 provides a framework for measuring the fair value of assets and liabilities. This framework is intended to provide increased consistency in how fair value determinations are made under various existing accounting standards that permit, or in some cases, require estimates of fair-market value. This standard also expanded financial statement disclosure requirements about a company’s use of fair-value measurements, including the effect of such measure on earnings. The cost of securities sold is based on the specific identification method.
	The Company’s investment securities (common stocks and mutual funds) are classified as available for sale and are stated at fair value based on quoted market prices, and as such are classified as Level 1 assets. The Company determines the fair value of its U.S. Treasury Notes, Government Securities and Corporate Bonds by utilizing monthly valuation statements that are provided by its broker, and the Company utilizes third party pricing sources to validate such statements. The broker determines the investment valuation by utilizing the bid price in the market. As such, these investments are classified as Level 2 assets.
	Assets or liabilities that have recurring fair value measurements are shown below as of December 31, 2013 and December 31, 2012:
				Fair Value Measurements at Reporting Date Using
		Total as of		Quoted Prices in				Significant Other				Significant
				Active Markets				Observable				Unobservable
				for Identical				Inputs				Inputs
				Assets
	Description	31-Dec-13		(Level I)				(Level 2)				(Level 3)
	Cash & Cash Equivalents	$	309,591,724	$	309,591,724			$	—			$	—
	Long-Term Investments:
	Common Stocks	33,282,439		33,282,439				—				—
	Mutual Funds – Equity	73,723,083		73,723,083				—				—
	Total	$	416,597,246	$	416,597,246			$	—			$	—
				Fair Value Measurements at Reporting Date Using
		Total as of		Quoted Prices in				Significant Other				Significant
				Active Markets				Observable				Unobservable
				for Identical				Inputs				Inputs
				Assets
	Description	December 31, 2012		(Level I)				(Level 2)				(Level 3)
	Cash & Cash Equivalents	$	389,678,664	$	389,678,664			$	—			$	—
	Short-Term Investments:
	Certificate of Deposit	510,881		—				510,881				—
	Government Securities	38,522,471		—				38,522,471				—
	U.S. Treasury Notes	15,020,350		—				15,020,350				—
	Corporate Bonds	6,563,228		—				6,563,228				—
	Other	185,926		185,926				—				—
	Long-Term Investments:
	Corporate Bonds	2,180,780		—				2,180,780				—
	Common Stocks	53,283,201		53,283,201				—				—
	Mutual Funds – Equity	86,109,053		86,109,053				—				—
	Other – Equity	261,000		261,000				—				—
	Total	$	592,315,554	$	529,517,844			$	62,797,710			$	—
	The amortized cost, unrealized gains and losses, and market value of investment securities are shown as of December 31, 2013 and 2012:
		Unrealized
	2013	Cost		Gains					Losses					Market Value
	Long-Term Investments:
	Common Stocks	22,799,035		10,532,007					(48,603		)			33,282,439
	Mutual Funds-Equity	54,256,577		19,466,506					—					73,723,083
	Total	$	77,055,612	$	29,998,513		—		$	(48,603	)	—		$	107,005,522
		Unrealized
	2012	Cost		Gains				Losses				Market Value
	Short-Term Investments:
	Certificate of Deposit	$	510,881	$	—			$	—			$	510,881
	Government Securities	$	38,514,411	$	9,004			$	(944	)		$	38,522,471
	U.S. Treasury Notes	15,018,810		2,602				(1,062		)		15,020,350
	Corporate Bonds	6,529,758		33,470				—				6,563,228
	Other	185,926		—				—				185,926
	Long-Term Investments:
	Corporate Bonds	2,174,948		5,832				—				2,180,780
	Common Stocks	40,893,121		12,781,501				(391,421		)		53,283,201
	Mutual Funds-Equity	75,321,640		11,082,714				(295,301		)		86,109,053
	Other-Equity	238,506		22,494				—				261,000
	Total	$	179,388,001	$	23,937,617			(688,728		)		$	202,636,890
	Unrealized losses on investments as of December 31, 2013 are as follows:
		Aggregate Unrealized Losses		Aggregate Fair Value
	Less than one year	$	48,603	$	1,886,080
	Unrealized losses on investments as of December 31, 2012 are as follows:
		Aggregate Unrealized Losses		Aggregate Fair Value
	Less than one year	$	688,728	$	22,887,686
	ASC 320, “Accounting for Certain Investments in Debt and Equity Securities,” as amended and interpreted, provides guidance on determining when an investment is other-than-temporarily impaired. The Company reviews its fixed income and equity investment portfolio for any unrealized losses that would be deemed other-than-temporary and require the recognition of an impairment loss in income. If the cost of an investment exceeds its fair value, the Company evaluates, among other factors, general market conditions, the duration and extent to which the fair value is less than cost, and the Company’s intent and ability to hold the investments. Management also considers the type of security, related-industry and sector performance, as well as published investments ratings and analyst reports, to evaluate its portfolio. Once a decline in fair value is determined to be other-than-temporary, an impairment charge is recorded and new cost basis in the investment is established. If market, industry, and/or investee conditions deteriorate, the Company may incur future impairments. No investments were considered to be other-than-temporary impaired in 2013 and 2012.
Fair Value of Financial Instruments	'
	Fair Value of Financial Instruments
	The Company’s financial instruments consist of cash and cash equivalents, investments, accounts receivable accounts payable, short and long term debt. The Company’s estimate of the fair values of these financial instruments approximates their carrying amounts at December 31, 2013 and 2012.
Inventories	'
	Inventories
	Inventories include material, direct labor and manufacturing overhead and are valued at the lower of first-in, first-out (FIFO) cost or market. Inventories consisted of the following as of December 31, 2013 and 2012.
		2013		2012
	Raw materials	$	75,081,810	$	114,750,525
	Work-in-process	21,409,976		24,588,734
	Finished goods	23,582,378		20,591,007
	Total Inventory	$	120,074,164	$	159,930,266
	Allowances for slow-moving and obsolete inventories were $6.9 million and $7.8 million at December 31, 2013 and 2012. The year-over-year decrease in the allowance was primarily the result of reductions in raw materials inventory.
Plant and Equipment	'
	Plant and Equipment
	Plant and equipment are stated at cost. Depreciation and amortization are computed for financial reporting purposes using the straight-line method, with estimated useful lives of 7 to 40 years for buildings and improvements, and 3 to 10 years for machinery and equipment. Depreciation expense was approximately $55.0 million, $48.5 million and $41.6 million in 2013, 2012 and 2011, respectively.
Impairment of Disposal of Long-Lived Assets	'
	Impairment of Disposal of Long-Lived Assets
	The Company reviews long-lived assets, including property, plant and equipment and other intangible assets with definite lives, for impairment whenever events or changes in circumstances indicate that the asset’s carrying amount of an asset may not be recoverable. The Company conducts its long-lived asset impairment analysis in accordance with ASC 360-10-15, “Impairment or Disposal of Long-Lived Assets.” ASC 360-10-15 requires the Company to group assets and liabilities at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities and evaluate the asset group against the sum of the undiscounted future cash flows. If the undiscounted cash flows do not indicate the carrying amount of the asset is recoverable, an impairment charge is measured as the amount by which the carrying amount of the asset group exceeds its fair value based on discounted cash flow analysis or appraisals.
Patents	'
	Patents
	The Company’s policy is to capitalize costs incurred to obtain patents. The cost of patents is amortized over their useful lives. The cost of patents in process is not amortized until issuance. The Company periodically obtains intellectual property rights, in the ordinary course of business, and the cost of the rights are amortized over their useful lives.
Goodwill and Other Intangible Assets	'
	Goodwill and Intangible Assets
	Goodwill represents the excess of fair value of assets acquired and liabilities assumed as of the acquisition date. In accordance with accounting guidance related to goodwill and other intangible assets, the Company will test for impairment of goodwill and indefinite-lived intangible assets annually in the fourth quarter and in certain situations between those annual dates, if interim indicators of impairment arise. Indefinite-lived intangible assets will be tested for impairment annually in the fourth quarter, by comparing the estimated fair value of the indefinite-lived intangible asset to the carrying value using a discounted cash flow approach. Intangible assets with a definite life are amortized over their useful life, which is the period over which the asset is expected to contribute directly or indirectly to future cash flows. Management will periodically assess the amortization period of intangible assets with definite lives based upon estimated future cash flows from related operations and tests for impairment when indicators arise.
	Given the timing of the acquisition, no impairment indicators arose during the year ended ended December 31, 2013 which would give reason for an interim test to be performed on goodwill or intangible assets.
Revenue Recognition	'
	Revenue Recognition
	The Company’s revenue is generated from sales of its products. Sales are recognized when the product is shipped and legal title has passed to the customer. The Company does not generate sales from arrangements with multiple deliverables.
Advertising and Promotional Materials	'
	Advertising and Promotional Materials
	All advertising and promotional costs are expensed as incurred and amounted to approximately $0.4 million, $1.0 million and $1.2 million, in 2013, 2012 and 2011, respectively.
Repairs and Maintenance	'
	Repairs and Maintenance
	Major renewals and improvements of property and equipment are capitalized, and repairs and maintenance are expensed as incurred. The Company incurred expenses relating to the repair and maintenance of plant and equipment of approximately $14.9 million, $13.8 million and $11.5 million, in 2013, 2012 and 2011, respectively.
Self-Insurance	'
	Self-Insurance
	The Company is self-insured for a portion of its risk on workers’ compensation and employee medical costs. The arrangements provide for stop loss insurance to manage the Company’s risk. Operations are charged with the cost of claims reported and an estimate of claims incurred but not reported based upon historical claims lag information and other data.
Product Warranty	'
	Product Warranty
	The Company periodically incurs product warranty costs. Any liabilities associated with product warranty are estimated based on known facts and circumstances and are not significant at December 31, 2013, 2012 and 2011. The Company does not offer extended warranties on its products.
Income Taxes	'
	Income Taxes
	The provision for income taxes is based on the earnings reported in the consolidated financial statements. Deferred income tax assets and liabilities are computed for differences between the financial statement and tax basis of assets and liabilities that will result in taxable or deductible amounts in the future. Such deferred income tax asset and liability computations are based on enacted tax laws and rates.
Earnings Per Share	'
	Earnings Per Share
	The following table reconciles the numerators and denominators used in the calculations of basic and diluted earnings per share (EPS) for each of the last three years:
		2013		2012				2011
	Numerators:
	Numerator for both basic and diluted EPS, net income	$	222,929,949	$	168,586,840			$	164,668,228
	Denominators:
	Denominator for basic EPS, weighted-average common shares outstanding	143,460,018		143,097,530				142,492,699
	Potentially dilutive shares resulting from stock option plans	814,153		870,501				1,784,109
	Denominator for diluted EPS	144,274,171		143,968,031				144,276,808
	For the years ended December 31, 2013, 2012 and 2011, 3,377,311, 3,332,719 and 1,253,824 shares, respectively, related to stock option plans were not included in diluted average common shares outstanding because their effect would be anti-dilutive.
Other Comprehensive Income (Loss)	'
	Other Comprehensive Income (Loss)
	Comprehensive income reflects the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. For the Company, comprehensive income represents net income adjusted for unrealized gains and losses on certain investments and foreign currency translation adjustments and is further detailed in Note 9 to the Consolidated Financial Statements.
Foreign Currency Translation	'
	Foreign Currency Translation
	The financial position and results of operations of the Company’s foreign subsidiaries are measured using the local currency as the functional currency. Assets and liabilities are translated at the exchange rate in effect at year-end. Income statement accounts are translated at the average rate of exchange in effect during the year. The resulting translation adjustment is recorded as a separate component of shareholders’ investment. Gains and losses arising from re-measuring foreign currency transactions into the appropriate currency are included in the determination of net income.
Stock-Based Compensation Plans	'
	Stock-Based Compensation Plans
	The Company accounts for stock-based compensation using the fair value recognition provisions of ASC 718, “Share-Based Payment.” As described more fully in Note 5, the Company provides compensation benefits under two stock option plans, a restricted stock plan and an employee stock purchase plan.
Estimates	'
	Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
New Accounting Standards	'
	New Accounting Standards
	In February 2013, FASB issued Accounting Standards Update No. 2013-02, “Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income” (“ASU 2013-12”).  ASU 2013-02 requires an entity to report the effect of significant reclassifications out of accumulated other comprehensive income.  The amended guidance does not change the current requirements for reporting net income or other comprehensive income in financial statements.  However, the amended guidance requires an entity to provide information regarding the amounts reclassified out of accumulated other comprehensive income by component, either on the face of the statement where net income is presented or in the notes to the condensed consolidated financial statements.  The amended guidance was effective for financial periods beginning after December 15, 2012.  ASU 2013-02 did not have a material effect on the Company's consolidated financial position or results of operations. Refer to Note 9, "Comprehensive Income," of the notes to consolidated financial statements for disclosures regarding other comprehensive income.

Summary_of_Significant_Account2

Summary of Significant Accounting and Reporting Policies (Tables)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Schedule of Allowance For Doubtful Accounts	'
	The following table presents the activity in the Company’s allowance for doubtful accounts:
		Beginning		Net				Deductions				Ending
		Balance		Additions/				and Other				Balance
				(Reductions)				Adjustments
				to Costs and
				Expenses
	Year Ended December 31, 2013:
	Allowance for Doubtful Accounts	$	3,400,000	$	—			$	197,612			$	3,202,388
	Year Ended December 31, 2012:
	Allowance for Doubtful Accounts	$	3,400,000	$	(577	)		577*				$	3,400,000
	Year Ended December 31, 2011:
	Allowance for Doubtful Accounts	$	4,300,000	$	(802,929	)		$	(97,071	)*		$	3,400,000
	*Represents excess recoveries and other adjustments over accounts written off.
Schedule of Assets or Liabilities Having Recurring Measurements	'
	Assets or liabilities that have recurring fair value measurements are shown below as of December 31, 2013 and December 31, 2012:
				Fair Value Measurements at Reporting Date Using
		Total as of		Quoted Prices in				Significant Other				Significant
				Active Markets				Observable				Unobservable
				for Identical				Inputs				Inputs
				Assets
	Description	31-Dec-13		(Level I)				(Level 2)				(Level 3)
	Cash & Cash Equivalents	$	309,591,724	$	309,591,724			$	—			$	—
	Long-Term Investments:
	Common Stocks	33,282,439		33,282,439				—				—
	Mutual Funds – Equity	73,723,083		73,723,083				—				—
	Total	$	416,597,246	$	416,597,246			$	—			$	—
				Fair Value Measurements at Reporting Date Using
		Total as of		Quoted Prices in				Significant Other				Significant
				Active Markets				Observable				Unobservable
				for Identical				Inputs				Inputs
				Assets
	Description	December 31, 2012		(Level I)				(Level 2)				(Level 3)
	Cash & Cash Equivalents	$	389,678,664	$	389,678,664			$	—			$	—
	Short-Term Investments:
	Certificate of Deposit	510,881		—				510,881				—
	Government Securities	38,522,471		—				38,522,471				—
	U.S. Treasury Notes	15,020,350		—				15,020,350				—
	Corporate Bonds	6,563,228		—				6,563,228				—
	Other	185,926		185,926				—				—
	Long-Term Investments:
	Corporate Bonds	2,180,780		—				2,180,780				—
	Common Stocks	53,283,201		53,283,201				—				—
	Mutual Funds – Equity	86,109,053		86,109,053				—				—
	Other – Equity	261,000		261,000				—				—
	Total	$	592,315,554	$	529,517,844			$	62,797,710			$	—
Schedule of Amortized Cost, Unrealized Gains And Losses, And Market Value of Investment Securities	'
	The amortized cost, unrealized gains and losses, and market value of investment securities are shown as of December 31, 2013 and 2012:
		Unrealized
	2013	Cost		Gains					Losses					Market Value
	Long-Term Investments:
	Common Stocks	22,799,035		10,532,007					(48,603		)			33,282,439
	Mutual Funds-Equity	54,256,577		19,466,506					—					73,723,083
	Total	$	77,055,612	$	29,998,513		—		$	(48,603	)	—		$	107,005,522
		Unrealized
	2012	Cost		Gains				Losses				Market Value
	Short-Term Investments:
	Certificate of Deposit	$	510,881	$	—			$	—			$	510,881
	Government Securities	$	38,514,411	$	9,004			$	(944	)		$	38,522,471
	U.S. Treasury Notes	15,018,810		2,602				(1,062		)		15,020,350
	Corporate Bonds	6,529,758		33,470				—				6,563,228
	Other	185,926		—				—				185,926
	Long-Term Investments:
	Corporate Bonds	2,174,948		5,832				—				2,180,780
	Common Stocks	40,893,121		12,781,501				(391,421		)		53,283,201
	Mutual Funds-Equity	75,321,640		11,082,714				(295,301		)		86,109,053
	Other-Equity	238,506		22,494				—				261,000
	Total	$	179,388,001	$	23,937,617			(688,728		)		$	202,636,890
Schedule of Unrealized Losses on Investments	'
	Unrealized losses on investments as of December 31, 2013 are as follows:
		Aggregate Unrealized Losses		Aggregate Fair Value
	Less than one year	$	48,603	$	1,886,080
	Unrealized losses on investments as of December 31, 2012 are as follows:
		Aggregate Unrealized Losses		Aggregate Fair Value
	Less than one year	$	688,728	$	22,887,686
Schedule of Inventories	'
	Inventories consisted of the following as of December 31, 2013 and 2012.
		2013		2012
	Raw materials	$	75,081,810	$	114,750,525
	Work-in-process	21,409,976		24,588,734
	Finished goods	23,582,378		20,591,007
	Total Inventory	$	120,074,164	$	159,930,266
Schedule of Earnings Per Share Basic and Diluted	'
	The following table reconciles the numerators and denominators used in the calculations of basic and diluted earnings per share (EPS) for each of the last three years:
		2013		2012				2011
	Numerators:
	Numerator for both basic and diluted EPS, net income	$	222,929,949	$	168,586,840			$	164,668,228
	Denominators:
	Denominator for basic EPS, weighted-average common shares outstanding	143,460,018		143,097,530				142,492,699
	Potentially dilutive shares resulting from stock option plans	814,153		870,501				1,784,109
	Denominator for diluted EPS	144,274,171		143,968,031				144,276,808

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Schedule of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits	'
	The Company follows the provisions of the Financial Accounting Standards Codification 740 (“ASC 740”), “Accounting for Uncertainty in Income Taxes.” A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:
		2013				2012				2011
	Beginning of year	$	4,168,000			$	2,476,000			$	2,483,000
	Additions based on tax positions related to the current year	1,595,000				785,000				1,105,000
	Additions for tax positions in prior years	1,633,000				907,000				208,000
	Reductions for tax positions in prior years	(45,000		)		—				(78,000		)
	Reductions as a result of completed audit examinations	—				—				(1,242,000		)
	End of year	$	7,351,000			$	4,168,000			$	2,476,000
Schedule of Components of Provision For Income Taxes	'
	The components of the provision for income taxes are as follows:
		2013				2012				2011
	Currently payable:
	Federal	$	95,285,094			$	76,507,760			$	63,307,583
	State	3,259,000				2,450,000				1,663,000
	Foreign	1,353,000				1,238,000				850,000
	Total	99,897,094				80,195,760				65,820,583
	Net deferred:
	Primarily federal	5,237,000				843,000				13,943,000
	Provision for income taxes	$	105,134,094			$	81,038,760			$	79,763,583
Schedule of Effective Income Tax Rates Different From Statutory Federal Income Tax Rates	'
	The effective income tax rates are different from the statutory federal income tax rates for the following reasons:
		2013			2012			2011
	Statutory federal income tax rate	35	%		35	%		35	%
	State income taxes, net of federal income tax benefit	0.6			0.6			0.1
	Domestic production exclusion	(3.1	)		(2.9	)		(2.3	)
	Research tax credit	(0.4	)		—			—
	Other	(0.1	)		(0.2	)		(0.2	)
	Effective income tax rate	32	%		32.5	%		32.6	%
Schedule of Deferred Income Tax Assets And Liabilities	'
	The tax effect of temporary differences which give rise to deferred income tax assets and liabilities at December 31, 2013 and 2012, are as follows:
		2013								2012
		Current				Non-Current				Current			Non-Current
	Assets:
	Accruals not currently deductible	$	2,970,671			$	182,803			$	3,721,183		$	186,997
	Stock based compensation	13,290,429				2,202,940				12,044,953			1,696,966
	Impairment loss on available-for-sale securities	—				175,091				—			327,308
	Intangible Assets	—				169,913				—			—
	Other	4,713,241				40,203				5,690,130			3,609
	Total deferred income tax assets	20,974,341				2,770,950				21,456,266			2,214,880
	Liabilities:
	Excess tax over book depreciation	—				(41,374,851		)		—			(47,704,521		)
	Patent costs	—				(1,792,968		)		—			(8,137,111		)
	Unrealized gain on investments	—				(10,482,468		)		—			(3,146,585		)
	Other	(558,249		)						(527,417		)	—
	Net deferred income taxes	$	20,416,092			$	(50,879,337	)		$	20,928,849		$	(56,773,337	)

StockBased_Compensation_Plans_

Stock-Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Schedule of Employee Stock Purchase Plan	'
	The following table summarizes shares sold to employees under the 2013 Plan and the prior plan in the years ended December 31, 2013, 2012 and 2011.
	Plan	2013			2012			2011		Cumulative Shares Issued in 2013		Weighted Average Fair Value 2013
	2013 Employee Stock Purchase Plan	51,462			—			—		51,462		$	22.64
	2003 Employee Stock Purchase Plan	26,170			102,498			68,630		1,200,000		$	17.01
	Total shares sold to employees	77,632			102,498			68,630
Employee Stock Option Plan	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Schedule of Weighted-Average Assumptions	'
	The fair value of each option grant in the Employee Stock Option Plan was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions for the indicated periods:
		2013				2012				2011
	Dividend yield (1)	2.6		%		2.7		%		2.7		%
	Expected volatility (2)	44.7		%		45.5		%		41.6		%
	Risk-free interest rate (3)	1.3		%		0.8		%		1.4		%
	Expected term of options (in years) (4)	4				4.1				4.2
	Weighted-average grant-date fair value	$	7			$	6			$	8
	(1)    Represents the Company's estimated cash dividend yield over the expected term of option grant.
	-2	Amount is determined based on analysis of historical price volatility of the Company's common stock. The expected volatility is based on the daily percentage change in the price of the stock over a period equal to the expected term of the option grant.
	(3)    Represents the U.S. Treasury yield over the expected term of the option grant.
	-4	Represents the period of time that options granted are expected to be outstanding. Based on analysis of historical option exercise activity, the Company has determined that all employee groups exhibit similar exercise and post-vesting termination behavior.
Summary of Stock Option Activity	'
	A summary of the status of the Company’s employee stock option plan at December 31, 2013, 2012 and 2011, and changes during the same periods are presented in the tables and narrative below:
		2013
		Shares			Wtd. Avg.				Wtd. Avg.		Aggregate
		0			Ex. Price				Remaining		Intrinsic
									Contract Life		Value
											0
	Outstanding at Beginning of Year	8,861			$	21
	Granted	2,731			25
	Exercised	(2,225	)		16						$	20,884
	Forfeited	(367	)		23
	Outstanding at End of Year	9,000			23				3.4 Yrs		$	85,633
	Exercisable at End of Year	2,745			$	23			2.3 Yrs		$	28,302
		2012
		Shares			Wtd. Avg.				Wtd. Avg.		Aggregate
		0			Ex. Price				Remaining		Intrinsic
									Contract Life		Value
											0
	Outstanding at Beginning of Year	7,555			$	21
	Granted	2,641			20
	Exercised	(689	)		15						$	3,810
	Forfeited	(646	)		21
	Outstanding at End of Year	8,861			21				3.4 Yrs		$	11,730
	Exercisable at End of Year	3,003			$	19			2.2 Yrs		$	7,617
		2011
		Shares			Wtd. Avg.				Wtd. Avg.		Aggregate
		0			Ex. Price				Remaining		Intrinsic
									Contract Life		Value
											0
	Outstanding at Beginning of Year	6,805			$	17
	Granted	2,462			29
	Exercised	(1,497	)		16						$	20,659
	Forfeited	(215	)		19
	Outstanding at End of Year	7,555			21				3.5 Yrs		$	66,295
	Exercisable at End of Year	2,024			$	17			2.3 Yrs		$	26,218
Schedule of Non-Vested Stock Option Activity	'
	A summary of the status of the Company’s non-vested employee stock option activity for the years ended December 31, 2013, 2012, and 2011, are presented in the table and narrative below:
		2013							2012					2011
		Shares			Wtd. Avg				Shares			Wtd. Avg		Shares		Wtd. Avg
		0			Grant				0			Grant		0		Grant
					Date							Date				Date
					Fair Value							Fair Value				Fair Value
	Nonvested Stock Options at Beginning of Year	5,858			$	6			5,530			$	6	5,038		$	5
	Granted	2,731			7				2,641			6		2,462		8
	Vested	(2,022	)		6				(1,936	)		5		(1,766	)	5
	Forfeited	(313	)		7				(377	)		6		(204	)	5
	Nonvested Stock Options at End of Year	6,254			$	7			5,858			$	6	5,530		$	6
Non-Employee Director Stock Option Plan	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Schedule of Weighted-Average Assumptions	'
	The fair value of each option grant in the Non-employee Director Stock Option Plans was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions for the indicated periods:
		2013				2012				2011
	Dividend yield (1)	2.7		%		2.6		%		2.7		%
	Expected volatility (2)	45.9		%		44.5		%		40.5		%
	Risk-free interest rate (3)	1.9		%		1.7		%		3.2		%
	Expected term of options (in years) (4)	7				6.8				6.5
	Weighted-average grant-date fair value	$	9			$	8			$	11
	(1)    Represents the Company's estimated cash dividend yield over the expected term of option grant.
	-2	Amount is determined based on analysis of historical price volatility of the Company's common stock. The expected volatility is based on the daily percentage change in the price of the stock over a period equal to the expected term of the option grant.
	(3)    Represents the U.S. Treasury yield over the expected term of the option grant.
	-4	Represents the period of time that options granted are expected to be outstanding. Based on analysis of historical option exercise activity, the Company has determined that non-employee directors exhibit similar exercise and post-vesting termination behavior.
Summary of Stock Option Activity	'
	A summary of the status of the Company’s Non-employee Director Stock Option Plan at December 31, 2013, 2012, and 2011, and changes during the same periods are presented in the tables and narrative below:
		2013
		Shares			Wtd. Avg.				Wtd. Avg.		Aggregate
		0			Ex. Price				Remaining		Intrinsic
									Contract Life		Value
											0
	Outstanding at Beginning of Year	234			$	21
	Granted	42			25
	Exercised	(45	)		20						$	300
	Forfeited	—			—
	Outstanding at End of Year	231			22				6.4 Yrs		$	2,491
	Exercisable at End of Year	231			$	22			6.4 Yrs		$	2,491
		2012
		Shares			Wtd. Avg.				Wtd. Avg.		Aggregate
		0			Ex. Price				Remaining		Intrinsic
									Contract Life		Value
											0
	Outstanding at Beginning of Year	192			$	21
	Granted	42			22
	Exercised	—			—
	Forfeited	—			—
	Outstanding at End of Year	234			21				6.4 Yrs		$	225
	Exercisable at End of Year	234			$	21			6.4 Yrs		$	225
		2011
		Shares			Wtd. Avg.				Wtd. Avg.		Aggregate
		0			Ex. Price				Remaining		Intrinsic
									Contract Life		Value
											0
	Outstanding at Beginning of Year	244			$	18
	Granted	42			32
	Exercised	(94	)		17						$	1,362
	Forfeited	—			—
	Outstanding at End of Year	192			21				6.8 Yrs		$	1,740
	Exercisable at End of Year	192			$	21			6.8 Yrs		$	1,740
Schedule of Non-Vested Stock Option Activity	'
	A summary of the status of the Company’s non-vested Non-employee Director Stock Option Plan activity for the years ended December 31, 2013, 2012, and 2010, are presented in the table and narrative below:
		2013							2012					2011
		Shares			Wtd. Avg				Shares			Wtd. Avg		Shares		Wtd. Avg
		0			Grant Date				0			Grant Date		0		Grant Date
					Fair Value							Fair Value				Fair Value
	Nonvested stock options at Beginning of Year	—			$	—			—			$	—	—		$	—
	Granted	42			9				42			8		42		11
	Vested	(42	)		9				(42	)		8		(42	)	11
	Forfeited								—			—		—		—
	Nonvested stock options at End of Year	—			$	—			—			$	—	—		$	—

Segment_Reporting_Tables

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Schedule of Automotive and Other Segment Reporting	'
	ASC 280, “Disclosures About Segments of an Enterprise and Related Information,” requires that a public enterprise report financial and descriptive information about its reportable operating segments subject to certain aggregation criteria and quantitative thresholds. Operating segments are defined by ASC 280 as components of an enterprise about which separate financial information is available that is evaluated regularly by the chief operating decision-makers in deciding how to allocate resources and in assessing performance.
		2013				2012			2011
	Revenue:
	Automotive Products
	United States	$	400,654,021			$	382,308,501		$	334,692,637
	Germany	244,949,664				239,081,723			248,495,295
	Japan	123,884,470				100,422,507			76,123,221
	Other	374,499,972				355,160,210			343,850,209
	Other	27,876,044				22,586,580			20,600,687
	Total	$	1,171,864,171			$	1,099,559,521		$	1,023,762,049
	Income (Loss) from Operations:
	Automotive Products	$	298,465,299			$	231,713,972		$	231,030,145
	Other	6,276,514				2,741,260			337,780
	Total	$	304,741,813			$	234,455,232		$	231,367,925
	Assets:
	Automotive Products	$	1,290,801,674			$	619,337,527		$	566,395,900
	Other	9,001,278				8,010,779			8,993,853
	Corporate	464,285,482				638,343,029			600,637,249
	Total	$	1,764,088,434			$	1,265,691,335		$	1,176,027,002
	Depreciation & Amortization:
	Automotive Products	$	58,723,222			$	47,976,800		$	40,314,620
	Other	316,836				317,534			320,900
	Corporate	3,814,097				1,885,489			1,999,164
	Total	$	62,854,155			$	50,179,823		$	42,634,684
	Capital Expenditures:
	Automotive Products	$	54,020,792			$	113,611,526		$	115,377,859
	Other	301,697				228,635			58,996
	Corporate	1,057,968				3,634,288			4,740,875
	Total	$	55,380,457			$	117,474,449		$	120,177,730
Schedule of Automotive Customers Individually Accounted For 10% or More of Net Sales	'
	During the years ended December 31, 2013, 2012 and 2011, approximately 7% , 8% and 9% of the Company’s net sales were invoiced and paid in foreign currencies respectively.
	In 2013, the Company had three automotive customers (includes direct sales to OEM customers and sales through their Tier 1 suppliers), which individually accounted for 10% or more of net sales as follows:
		Toyota Motor Corporation		VW/Audi			Hyundai/Kia		Daimler AG		General Motors
	2013	13	%	14	%		#		11	%	#
	2012	14	%	14	%		11	%	11	%	10	%
	2011	12	%	15	%		11	%	11	%	12	%
	# - Less than 10 percent.

Quarterly_Financial_Informatio1

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Schedule of Quarterly Financial Information	'
	The following table sets forth selected financial information for all of the quarters during the years ended December 31, 2013 and 2012 (in thousands, except per share data):
		First				Second				Third				Fourth
		2013		2012		2013		2012		2013		2012		2013		2012
	Net Sales	$	269,499	$	290,707	$	286,974	$	280,256	$	288,622	$	268,248	$	326,770	$	260,349
	Gross Profit	93,464		100,826		102,613		92,757		105,962		90,116		128,694		89,119
	Operating Income	63,854		65,501		71,596		57,512		73,656		57,623		95,636		53,819
	Net Income	45,431		46,345		52,097		40,767		55,521		41,877		69,881		39,599
	Earnings Per Share (Diluted)	$	0.32	$	0.32	$	0.36	$	0.28	$	0.38	$	0.29	$	0.48	$	0.28
	Earnings Per Share (Basic)	$	0.32	$	0.32	$	0.36	$	0.28	$	0.39	$	0.29	$	0.48	$	0.28

Comprehensive_Income_Tables

Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2013
Comprehensive Income [Abstract]	'
Schedule of Accumulated Other Comprehensive Income (Loss)	'
	Comprehensive income reflects the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. For the Company, comprehensive income represents net income adjusted for unrealized gains and losses on certain investments and foreign currency translation adjustments.
		For the Twelve Months ended December 31,
		2013				2012				2011
	Foreign currency translation adjustments:
	Balance at beginning of period	$	2,458,933			$	2,129,957			$	566,903
	Other Comprehensive income before reclassifications	48,989				328,976				1,563,054
	Amounts reclassified from accumulated other comprehensive income	—				—				—
	Net current-period change	48,989				328,976				1,563,054
	Balance at end of period	2,507,922				2,458,933				2,129,957
	Unrealized gains(losses) on available-for-sale securities:
	Balance at beginning of period	15,111,778				10,412,246				21,750,000
	Other Comprehensive income before reclassifications	16,139,845				10,138,902				(7,012,974		)
	Amounts reclassified from accumulated other comprehensive income	(11,784,182		)		(5,439,370		)		(4,324,780		)
	Net current-period change	4,355,663				4,699,532				(11,337,754		)
	Balance at end of period	19,467,441				15,111,778				10,412,246
	Accumulated other comprehensive income, end of period	$	21,975,363			$	17,570,711			$	12,542,203
	All amounts are shown net of tax. Amounts in parentheses indicate debits.
Reclassification out of Accumulated Other Comprehensive Income	'
	The following table presents details of reclassifications out of other comprehensive income for the twelve months ended December 31, 2013, 2012 and 2011.
	Details about Accumulated Other Comprehensive Income Components		Amounts Reclassified from Other Comprehensive Income											Affected Line item in the Statement of Consolidated Income
			For the Twelve Months ended December 31,
			2013				2012				2011
	Unrealized gains and (losses) on available-for-sale securities
	Realized gain (loss) on sale of securities		$	18,129,511			$	8,368,261			$	6,653,508		Other, net
	Provision for Income Taxes		(6,345,329		)		(2,928,891		)		(2,328,728		)	Provision for Income Taxes
	Total reclassifications for the period		$	11,784,182			$	5,439,370			$	4,324,780		Net of tax

Business_Combinations_Tables

Business Combinations (Tables)	12 Months Ended
	Dec. 31, 2013
Business Combinations [Abstract]	'
Schedule of Preliminary Allocation of the Purchase Price	'
	The below table shows the preliminary allocation of the purchase price as of September 30, 2013 and subsequent adjustments to the preliminary allocation as of December 31, 2013.
	Net Assets Acquired	Fair Value as of September 30, 2013		Fair Value Adjustments			Other Adj			Fair Value as of December 31, 2013
	Prepaid Service Agreement Costs (1)	$	3,383,000	$	—		$	(3,383,000	)	$	—
	Personal Property	4,430,986		3,683,614			—			8,114,600
	Real Property	1,060,000		—			—			1,060,000
	HomeLink® Trade Names and Trademarks	47,000,000		5,000,000			—			52,000,000
	HomeLink®Technology	166,000,000		14,000,000			—			180,000,000
	Existing Customer Platforms	43,000,000		—			—			43,000,000
	Exclusive Licensing Agreement	87,000,000		9,000,000			—			96,000,000
	Accounts Receivable	7,719,302		—			3,400,145			11,119,447
	Net Customer Tooling	956,665		—			26,741			983,406
	Fair Value of Acquired Assets	360,549,953		31,683,614			43,886			392,277,453
	Other adjustments	—		—			(1,492,398		)	(1,492,398		)
	Goodwill	337,557,061		(31,683,614		)	1,492,398			307,365,845
	Total Cash Consideration	$	698,107,014	$	—		$	43,886		$	698,150,900
	(1) - The Company used the prepaid service agreement costs to offset payments due to the Seller in the quarter ended , December 31, 2013.
Schedule of Pro Forma Information	'
	The following unaudited pro forma condensed consolidated statement of income for twelve month periods ended December 31, and 2012 include pro-forma adjustments to reflect the effect of the acquisition as if it had occurred on January 1, 2013. This unaudited pro forma consolidated statement of income is provided for informational purposes only and does not purport to be indicative of the results which would have actually been attained had the acquisition occurred on January 1, 2013 or that may be attained in the future.
	PRO FORMA CONDENSED CONSOLIDATED STATEMENT OF INCOME
	Twelve Months Ended December 31,
		2013		2012
	Net Sales	$	1,271,320	$	1,216,009
	Net Income	253,678		205,023

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Schedule of Goodwill	'
	The following table shows the carrying value of Goodwill as of December 31, 2012 and December 31, 2013.
		Carrying Amount
	Balance as of December 31, 2012	$	—
	Acquisitions	307,365,845
	Divestitures	—
	Impairments	—
	Other	—
	Balance as of December 31, 2013	$	307,365,845
Schedule of Intangible Assets	'
	The Intangible assets and related change in carrying values are shown below as of December 31, 2013. Please see Note 10 for a reconciliation of preliminary asset valuations as of September 30, 2013 and related adjustments to intangible asset values as of December 31, 2013:
	Other Intangible Assets	Gross		Accumulated Amortization			Net		Assumed Useful Life
	HomeLink®Trade Names and Trademarks	$	52,000,000	$	—		$	52,000,000	Indefinite
	HomeLink® Technology	180,000,000		(3,750,000		)	$	176,250,000	12 years
	Existing Customer Platforms	43,000,000		(1,075,000		)	$	41,925,000	10 years
	Exclusive Licensing Agreement	96,000,000		—			$	96,000,000	Indefinite
	Total other identifiable intangible assets	$	371,000,000	$	(4,825,000	)	$	366,175,000

Summary_of_Significant_Account3

Summary of Significant Accounting and Reporting Policies (Narrative) (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Summary Of Significant Accounting And Reporting Policies [Line Items]	'	'	'
Allowance for obsolete and slow moving inventories	$6.90	$7.80	'
Depreciation expense	55	48.5	41.6
Advertising and promotional costs	0.4	1	1.2
Repair and maintenance of plant and equipment	$14.90	$13.80	$11.50
Shares related to stock plans not included in diluted average common shares outstanding because their effect would be antidilutive	3,377,311	3,332,719	1,253,824
Buildings and improvements | Minimum	'	'	'
Summary Of Significant Accounting And Reporting Policies [Line Items]	'	'	'
Minimum estimated useful life, in years	'7 years	'	'
Buildings and improvements | Maximum	'	'	'
Summary Of Significant Accounting And Reporting Policies [Line Items]	'	'	'
Minimum estimated useful life, in years	'40 years	'	'
Machinery and equipment | Minimum	'	'	'
Summary Of Significant Accounting And Reporting Policies [Line Items]	'	'	'
Minimum estimated useful life, in years	'3 years	'	'
Machinery and equipment | Maximum	'	'	'
Summary Of Significant Accounting And Reporting Policies [Line Items]	'	'	'
Minimum estimated useful life, in years	'10 years	'	'

Summary_of_Significant_Account4

Summary of Significant Accounting and Reporting Policies (Schedule Of Allowance For Doubtful Accounts) (Details) (Allowance for Doubtful Accounts, USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Allowance for Doubtful Accounts	'	'	'
Activity in the Companybs allowance for doubtful accounts	'	'	'
Beginning Balance	$3,400,000	$3,400,000	$4,300,000
Net Additions/ (Reductions) to Costs and Expenses	0	-577	-802,929
Deductions and Other Adjustments	197,612	577	-97,071
Ending Balance	$3,202,388	$3,400,000	$3,400,000

Summary_of_Significant_Account5

Summary of Significant Accounting and Reporting Policies (Schedule of Assets or Liabilities Having Recurring Measurements) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Cash & Cash Equivalents	$309,591,724	$389,678,664	'	'
Cash and cash equivalents	309,591,724	389,678,664	357,986,774	348,349,773
Total	416,597,246	592,315,554	'	'
Certificate of Deposit	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	510,881	'	'
Government Securities	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	38,522,471	'	'
U.S. Treasury Notes	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	15,020,350	'	'
Corporate Bonds	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	6,563,228	'	'
Long-Term Investments	'	2,180,780	'	'
Other	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	185,926	'	'
Common Stocks	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Long-Term Investments	33,282,439	53,283,201	'	'
Mutual Funds b Equity	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Long-Term Investments	73,723,083	86,109,053	'	'
Other b Equity	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Long-Term Investments	'	261,000	'	'
Level 1	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Cash & Cash Equivalents	'	389,678,664	'	'
Cash and cash equivalents	309,591,724	'	'	'
Total	416,597,246	529,517,844	'	'
Level 1 | Certificate of Deposit	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	0	'	'
Level 1 | Government Securities	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	0	'	'
Level 1 | U.S. Treasury Notes	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	0	'	'
Level 1 | Corporate Bonds	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	0	'	'
Long-Term Investments	'	0	'	'
Level 1 | Other	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	185,926	'	'
Level 1 | Common Stocks	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Long-Term Investments	33,282,439	53,283,201	'	'
Level 1 | Mutual Funds b Equity	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Long-Term Investments	73,723,083	86,109,053	'	'
Level 1 | Other b Equity	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Long-Term Investments	'	261,000	'	'
Level 2	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Cash & Cash Equivalents	0	0	'	'
Total	0	62,797,710	'	'
Level 2 | Certificate of Deposit	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	510,881	'	'
Level 2 | Government Securities	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	38,522,471	'	'
Level 2 | U.S. Treasury Notes	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	15,020,350	'	'
Level 2 | Corporate Bonds	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	6,563,228	'	'
Long-Term Investments	'	2,180,780	'	'
Level 2 | Other	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	0	'	'
Level 2 | Common Stocks	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Long-Term Investments	0	0	'	'
Level 2 | Mutual Funds b Equity	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Long-Term Investments	0	0	'	'
Level 2 | Other b Equity	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Long-Term Investments	'	0	'	'
Level 3	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Cash & Cash Equivalents	0	0	'	'
Total	'	'	'	'
Level 3 | Certificate of Deposit	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	0	'	'
Level 3 | Government Securities	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	0	'	'
Level 3 | U.S. Treasury Notes	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	0	'	'
Level 3 | Corporate Bonds	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	0	'	'
Long-Term Investments	'	0	'	'
Level 3 | Other	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Short-Term Investments	'	0	'	'
Level 3 | Common Stocks	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Long-Term Investments	0	0	'	'
Level 3 | Mutual Funds b Equity	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Long-Term Investments	0	0	'	'
Level 3 | Other b Equity	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'
Long-Term Investments	'	$0	'	'

Summary_of_Significant_Account6

Summary of Significant Accounting and Reporting Policies (Schedule of Amortized Cost, Unrealized Gains And Losses, And Market Value Of Investment Securities) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	$77,055,612	$179,388,001
Gross Unrealized Gains	29,998,513	23,937,617
Gross Unrealized Losses	-48,603	-688,728
Market Value	107,005,522	202,636,890
Certificate of Deposit	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	'	510,881
Gross Unrealized Gains	'	0
Gross Unrealized Losses	'	0
Market Value	'	510,881
Government Securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	'	38,514,411
Gross Unrealized Gains	'	9,004
Gross Unrealized Losses	'	-944
Market Value	'	38,522,471
U.S. Treasury Notes	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	'	15,018,810
Gross Unrealized Gains	'	2,602
Gross Unrealized Losses	'	-1,062
Market Value	'	15,020,350
Corporate Bonds	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	'	6,529,758
Gross Unrealized Gains	'	33,470
Gross Unrealized Losses	'	0
Market Value	'	6,563,228
Other	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	'	185,926
Gross Unrealized Gains	'	0
Gross Unrealized Losses	'	0
Market Value	'	185,926
Corporate Bonds	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	'	2,174,948
Gross Unrealized Gains	'	5,832
Gross Unrealized Losses	'	0
Market Value	'	2,180,780
Common Stocks	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	22,799,035	40,893,121
Gross Unrealized Gains	10,532,007	12,781,501
Gross Unrealized Losses	-48,603	-391,421
Market Value	33,282,439	53,283,201
Mutual Funds b Equity	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	54,256,577	75,321,640
Gross Unrealized Gains	19,466,506	11,082,714
Gross Unrealized Losses	0	-295,301
Market Value	73,723,083	86,109,053
Other b Equity	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost	'	238,506
Gross Unrealized Gains	'	22,494
Gross Unrealized Losses	'	0
Market Value	'	$261,000

Summary_of_Significant_Account7

Summary of Significant Accounting and Reporting Policies (Schedule of Unrealized Losses on Investments) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Accounting Policies [Abstract]	'	'
Aggregate Unrealized Losses, Less than one year	$48,603	$688,728
Continuous unrealized loss position, Aggregate Fair Value	$1,886,080	$22,887,686

Summary_of_Significant_Account8

Summary of Significant Accounting and Reporting Policies (Schedule of Inventories) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Accounting Policies [Abstract]	'	'
Raw materials	$75,081,810	$114,750,525
Work-in-process	21,409,976	24,588,734
Finished goods	23,582,378	20,591,007
Total Inventory	$120,074,164	$159,930,266

Summary_of_Significant_Account9

Summary of Significant Accounting and Reporting Policies (Schedule of Earnings Per Share, Basic And Diluted) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Numerators:	'	'	'	'	'	'	'	'	'	'	'
Numerator for both basic and diluted EPS, net income	$69,881,000	$55,521,000	$52,097,000	$45,431,000	$39,599,000	$41,877,000	$40,767,000	$46,345,000	$222,929,949	$168,586,840	$164,668,228
Denominators:	'	'	'	'	'	'	'	'	'	'	'
Denominator for basic EPS, weighted-average common shares outstanding	'	'	'	'	'	'	'	'	143,460,018	143,097,530	142,492,699
Potentially dilutive shares resulting from stock option plans	'	'	'	'	'	'	'	'	814,153	870,501	1,784,109
Denominator for diluted EPS	'	'	'	'	'	'	'	'	144,274,171	143,968,031	144,276,808

Debt_and_Financing_Arrangement1

Debt and Financing Arrangements (Details) (USD $)

0 Months Ended

12 Months Ended

0 Months Ended

3 Months Ended

Sep. 30, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 27, 2013

Sep. 27, 2013

Sep. 27, 2013

Sep. 27, 2013

Sep. 27, 2013

Other, net

Other, net

Other, net

Base Rate

LIBOR Rate

Minimum

Minimum

Maximum

Maximum

Credit Agreement

Credit Agreement

Revolving Facility

Term Loan

Swing Loans

Letters of Credit

Base Rate

LIBOR Rate

Base Rate

LIBOR Rate

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Principal amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$150,000,000

$150,000,000

'

'

Additional principal amount available

'

'

'

'

'

'

'

'

'

'

'

'

'

'

75,000,000

'

'

20,000,000

20,000,000

Description of variable rate basis

'

'

'

'

'

'

'

'base

'LIBOR

'

'

'

'

'

'

'

'

'

'

Basis spread on variable rate

1.00%

'

'

'

'

'

'

0.50%

'

0.00%

1.00%

0.75%

1.75%

'

'

'

'

'

'

Amount borrowed

'

'

'

'

'

'

'

'

'

'

'

'

'

'

275,000,000

125,000,000

150,000,000

'

'

Debt repayment

'

1,875,000

0

0

'

'

'

'

'

'

'

'

'

1,900,000

'

'

'

'

'

Payments of financing charges

'

'

'

'

900,000

0

0

'

'

'

'

'

'

'

'

'

'

'

'

Available borrowing capacity

'

'

'

'

'

'

'

'

'

'

'

'

'

$26,900,000

'

'

'

'

'

Income_Taxes_Narrative_Details

Income Taxes (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]	'	'	'
Unrecognized tax benefits accrued interest	$555,000	$250,000	'
Tax benefits associated with the exercise, vesting or disposition of stock under stock plans recognized as an adjustment of additional paid-in capital	7,400,000	1,500,000	7,900,000
Income taxes paid	$97,100,000	$63,400,000	$63,500,000

Income_Taxes_Schedule_Of_Recon

Income Taxes (Schedule Of Reconciliation Of Beginning And Ending Amount Of Unrecognized Tax Benefits ) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of the beginning and ending amount of unrecognized tax benefits	'	'	'
Beginning of year	$4,168,000	$2,476,000	$2,483,000
Additions based on tax positions related to the current year	1,595,000	785,000	1,105,000
Additions for tax positions in prior years	1,633,000	907,000	208,000
Reductions for tax positions in prior years	-45,000	0	-78,000
Reductions as a result of completed audit examinations	0	0	-1,242,000
End of year	$7,351,000	$4,168,000	$2,476,000

Income_Taxes_Schedule_Of_Compo

Income Taxes (Schedule Of Components Of Provision For Income Taxes) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Currently payable:	'	'	'
Federal	$95,285,094	$76,507,760	$63,307,583
State	3,259,000	2,450,000	1,663,000
Foreign	1,353,000	1,238,000	850,000
Total	99,897,094	80,195,760	65,820,583
Net deferred:	'	'	'
Primarily federal	5,237,000	843,000	13,943,000
Provision for income taxes	$105,134,094	$81,038,760	$79,763,583

Income_Taxes_Schedule_Of_Effec

Income Taxes (Schedule Of Effective Income Tax Rates Different From Statutory Federal Income Tax Rates) (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]	'	'	'
Statutory federal income tax rate	35.00%	35.00%	35.00%
State income taxes, net of federal income tax benefit	0.60%	0.60%	0.10%
Domestic production exclusion	-3.10%	-2.90%	-2.30%
Research tax credit	-0.40%	0.00%	0.00%
Other	-0.10%	-0.20%	-0.20%
Effective income tax rate	32.00%	32.50%	32.60%

Income_Taxes_Schedule_Of_Defer

Income Taxes (Schedule Of Deferred Income Tax Assets And Liabilities) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Current	'	'
Assets:	'	'
Accruals not currently deductible	$2,970,671	$3,721,183
Stock based compensation	13,290,429	12,044,953
Impairment loss on available-for-sale securities	0	0
Intangible Assets	0	0
Other	4,713,241	5,690,130
Total deferred income tax assets	20,974,341	21,456,266
Liabilities:	'	'
Excess tax over book depreciation	0	0
Patent costs	0	0
Unrealized gain on investments	0	0
Other	-558,249	-527,417
Net deferred income taxes	20,416,092	20,928,849
Non-Current	'	'
Assets:	'	'
Accruals not currently deductible	182,803	186,997
Stock based compensation	2,202,940	1,696,966
Impairment loss on available-for-sale securities	175,091	327,308
Intangible Assets	169,913	0
Other	40,203	3,609
Total deferred income tax assets	2,770,950	2,214,880
Liabilities:	'	'
Excess tax over book depreciation	-41,374,851	-47,704,521
Patent costs	-1,792,968	-8,137,111
Unrealized gain on investments	-10,482,468	-3,146,585
Other	'	0
Net deferred income taxes	($50,879,337)	($56,773,337)

Employee_Benefit_Plan_Details

Employee Benefit Plan (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Compensation and Retirement Disclosure [Abstract]	'	'	'
Company's contributions under 401(k) retirement savings plan	$2.80	$2.50	$2.30

StockBased_Compensation_Plans_1

Stock-Based Compensation Plans (Details) (USD $)

12 Months Ended

10 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2004

Dec. 31, 2002

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

31-May-13

Dec. 31, 2013

Dec. 31, 2003

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Employee Stock Option Plan

Employee Stock Option Plan

Non-Employee Director Stock Option Plan

Non-Employee Director Stock Option Plan

Restricted Stock Plan [Member]

Restricted Stock Plan [Member]

Restricted Stock Plan [Member]

Restricted Stock Plan [Member]

Employee Stock Purchase Plan [Member]

Employee Stock Purchase Plan [Member]

Employee Stock Purchase Plan [Member]

Employee Stock Purchase Plan, 2003 [Member]

Employee Stock Purchase Plan, 2003 [Member]

Employee Stock Purchase Plan, 2003 [Member]

Employee Stock Purchase Plan, 2013 [Member]

Employee Stock Purchase Plan, 2013 [Member]

Employee Stock Purchase Plan, 2013 [Member]

Minimum

Minimum

Minimum

Minimum

Maximum

Maximum

Maximum

Maximum

Employee Stock Option Plan

Restricted Stock Plan [Member]

Restricted Stock Plan [Member]

Restricted Stock Plan [Member]

Employee Stock Option Plan

Restricted Stock Plan [Member]

Restricted Stock Plan [Member]

Restricted Stock Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Options available for grant

'

'

'

'

18,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Options granted net of shares from canceled/expired options

'

'

'

15,723,739

'

549,240

84,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Option vesting period

'

'

'

'

'

'

'6 months

'

'

'

'

'

'

'

'

'

'

'

'

'

'1 year

'

'

'

'5 years

'

'

'

Share Based Compensation Arrangement By Share Based Payment Award, Award Expiration Period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'3 years

'

'

'

'7 years

'

'

'

Unrecognized compensation cost

'

'

'

$24,527,192

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted-average period for unrecognized compensation cost expected to be recognized

'

'

'

'2 years 2 months 6 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares approved

'

'

'

'

'

'

500,000

'

'

'

2,000,000

'

'

1,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Option expiration period, years

'

'

'

'

'

'

'10 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

ESPP discount rate

'

'

'

'

'

'

'

'

'

'

'

'

85.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Discount recognized as compensation expense

'

'

'

'

'

'

'

'

'

'

'

15.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares sold to employees during period

77,632

102,498

68,630

'

'

'

'

'

'

'

'

'

'

'

26,170

102,498

68,630

51,462

0

0

'

'

'

'

'

'

'

'

Cumulative shares sold to employees during period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,200,000

'

'

51,462

'

'

'

'

'

'

'

'

'

'

Weighted average fair value of shares sold

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$17.01

'

'

$22.64

'

'

'

'

'

'

'

'

'

'

Restricted period, maximum, in years

'

'

'

'

'

'

'

'10 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares granted with restriction period

187,090

225,730

140,900

'

'

'

'

768,200

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Restricted period for granted shares, in years

'

'

'

'

'

'

'

'5 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Market price

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$20.23

$17.27

$24.96

'

$32.83

$24.45

$30.25

Unearned stock-based compensation

'

'

'

'

'

'

'

9,762,379

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amortization expense

'

'

'

'

'

'

'

$2,760,446

$2,108,583

$2,039,377

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

StockBased_Compensation_Plans_2

Stock-Based Compensation Plans (Schedule of Weighted-Average Assumptions) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Stock Option Plan	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Dividend yield	2.60%	2.70%	2.70%
Expected volatility	44.70%	45.50%	41.60%
Risk-free interest rate	1.30%	0.80%	1.40%
Expected term of options (in years)	'4 years 0 months 0 days	'4 years 1 month 6 days	'4 years 2 months 12 days
Weighted-average grant-date fair value	$7	$6	$8
Non-Employee Director Stock Option Plan	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Dividend yield	2.70%	2.60%	2.70%
Expected volatility	45.90%	44.50%	40.50%
Risk-free interest rate	1.90%	1.70%	3.20%
Expected term of options (in years)	'7 years 0 months 0 days	'6 years 9 months 18 days	'6 years 6 months
Weighted-average grant-date fair value	$9	$8	$11

StockBased_Compensation_Plans_3

Stock-Based Compensation Plans (Summary of Stock Option Activity) (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Stock Option Plan	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]	'	'	'
Shares, Outstanding at Beginning of Year	8,861	7,555	6,805
Shares, Granted	2,731	2,641	2,462
Shares, Exercised	-2,225	-689	-1,497
Shares, Forfeited	-367	-646	-215
Shares, Outstanding at End of Year	9,000	8,861	7,555
Shares, Exercisable at End of Year	2,745	3,003	2,024
Wtd. Avg. Ex. Price, Outstanding at Beginning of Year (usd per share)	$21	$21	$17
Wtd. Avg. Ex. Price, Granted (usd per share)	$25	$20	$29
Wtd. Avg. Ex. Price, Exercised (usd per share)	$16	$15	$16
Wtd. Avg. Ex. Price, Forfeited (usd per share)	$23	$21	$19
Wtd. Avg. Ex. Price, Outstanding at End of Year (usd per share)	$23	$21	$21
Wtd. Avg. Ex. Price, Exercisable at End of Year (usd per share)	$23	$19	$17
Wtd. Avg. Remaining Contract Life, Outstanding at End of Year	'3 years 4 months 24 days	'3 years 4 months 24 days	'3 years 6 months
Wtd. Avg. Remaining Contract Life, Exercisable at End of Year	'2 years 3 months 18 days	'2 years 2 months 12 days	'2 years 3 months 18 days
Aggregate Intrinsic Value, Exercised	$20,884	$3,810	$20,659
Aggregate Intrinsic Value, Outstanding at End of Year	85,633	11,730	66,295
Aggregate Intrinsic Value, Exercisable at End of Year	28,302	7,617	26,218
Non-Employee Director Stock Option Plan	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]	'	'	'
Shares, Outstanding at Beginning of Year	234	192	244
Shares, Granted	42	42	42
Shares, Exercised	-45	0	-94
Shares, Forfeited	0	0	0
Shares, Outstanding at End of Year	231	234	192
Shares, Exercisable at End of Year	231	234	192
Wtd. Avg. Ex. Price, Outstanding at Beginning of Year (usd per share)	$21	$21	$18
Wtd. Avg. Ex. Price, Granted (usd per share)	$25	$22	$32
Wtd. Avg. Ex. Price, Exercised (usd per share)	$20	$0	$17
Wtd. Avg. Ex. Price, Forfeited (usd per share)	$0	$0	$0
Wtd. Avg. Ex. Price, Outstanding at End of Year (usd per share)	$22	$21	$21
Wtd. Avg. Ex. Price, Exercisable at End of Year (usd per share)	$22	$21	$21
Wtd. Avg. Remaining Contract Life, Outstanding at End of Year	'6 years 4 months 24 days	'6 years 4 months 24 days	'6 years 9 months 18 days
Wtd. Avg. Remaining Contract Life, Exercisable at End of Year	'6 years 4 months 24 days	'6 years 4 months 24 days	'6 years 9 months 18 days
Aggregate Intrinsic Value, Exercised	300	'	1,362
Aggregate Intrinsic Value, Outstanding at End of Year	2,491	225	1,740
Aggregate Intrinsic Value, Exercisable at End of Year	$2,491	$225	$1,740

StockBased_Compensation_Plans_4

Stock-Based Compensation Plans (Schedule of Non-Vested Stock Option Activity) (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Stock Option Plan	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]	'	'	'
Shares, Nonvested stock options at Beginning of Year	5,858	5,530	5,038
Shares, Granted	2,731	2,641	2,462
Shares, Vested	-2,022	-1,936	-1,766
Shares, Forfeited	-313	-377	-204
Shares, Nonvested stock options at End of Year	6,254	5,858	5,530
Wtd. Avg Grant Date Fair Value, Nonvested stock options at Beginning of Year (usd per share)	$6	$6	$5
Wtd. Avg Grant Date Fair Value, Granted (usd per share)	$7	$6	$8
Wtd. Avg Grant Date Fair Value, Vested (usd per share)	$6	$5	$5
Wtd. Avg Grant Date Fair Value, Forfeited (usd per share)	$7	$6	$5
Wtd. Avg Grant Date Fair Value, Nonvested stock options at End of Year (usd per share)	$7	$6	$6
Non-Employee Director Stock Option Plan	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]	'	'	'
Shares, Nonvested stock options at Beginning of Year	0	0	0
Shares, Granted	42	42	42
Shares, Vested	-42	-42	-42
Shares, Forfeited	'	0	0
Shares, Nonvested stock options at End of Year	0	0	0
Wtd. Avg Grant Date Fair Value, Nonvested stock options at Beginning of Year (usd per share)	$0	$0	$0
Wtd. Avg Grant Date Fair Value, Granted (usd per share)	$9	$8	$11
Wtd. Avg Grant Date Fair Value, Vested (usd per share)	$9	$8	$11
Wtd. Avg Grant Date Fair Value, Forfeited (usd per share)	'	$0	$0
Wtd. Avg Grant Date Fair Value, Nonvested stock options at End of Year (usd per share)	$0	$0	$0

Contingencies_Details

Contingencies (Details) (Litigation Settled [Member])	0 Months Ended
	Jun. 25, 2012	Oct. 05, 2012	Jul. 27, 2012
	co-defendant	complaint	complaint
	complaint
Loss Contingencies [Line Items]	'	'	'
Number of complaints filed	4	'	'
Number of co-defendants	1	'	'
Total number of customers cited as possible co-defendants	2	'	'
Number of complaints served	'	'	4
Number of complains answered	'	4	'
SmartBeam [Member]	'	'	'
Loss Contingencies [Line Items]	'	'	'
Number of complaints filed	2	'	'
Number of patents infringed upon	1	'	'
Monitoring System Products [Member]	'	'	'
Loss Contingencies [Line Items]	'	'	'
Number of complaints filed	2	'	'
Number of patents infringed upon	2	'	'

Segment_Reporting_Schedule_of_

Segment Reporting (Schedule of Automotive and Other Segment Reporting) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Revenues	$326,770,000	$288,622,000	$286,974,000	$269,499,000	$260,349,000	$268,248,000	$280,256,000	$290,707,000	$1,171,864,171	$1,099,559,521	$1,023,762,049
Income (Loss) from Operations	95,636,000	73,656,000	71,596,000	63,854,000	53,819,000	57,623,000	57,512,000	65,501,000	304,741,813	234,455,232	231,367,925
Assets	1,764,088,434	'	'	'	1,265,691,335	'	'	'	1,764,088,434	1,265,691,335	1,176,027,002
Depreciation & Amortization	'	'	'	'	'	'	'	'	62,854,155	50,179,823	42,634,684
Capital Expenditures	'	'	'	'	'	'	'	'	55,380,457	117,474,449	120,177,730
Automotive Products	'	'	'	'	'	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Income (Loss) from Operations	'	'	'	'	'	'	'	'	298,465,299	231,713,972	231,030,145
Assets	1,290,801,674	'	'	'	619,337,527	'	'	'	1,290,801,674	619,337,527	566,395,900
Depreciation & Amortization	'	'	'	'	'	'	'	'	58,723,222	47,976,800	40,314,620
Capital Expenditures	'	'	'	'	'	'	'	'	54,020,792	113,611,526	115,377,859
Other	'	'	'	'	'	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	27,876,044	22,586,580	20,600,687
Income (Loss) from Operations	'	'	'	'	'	'	'	'	6,276,514	2,741,260	337,780
Assets	9,001,278	'	'	'	8,010,779	'	'	'	9,001,278	8,010,779	8,993,853
Depreciation & Amortization	'	'	'	'	'	'	'	'	316,836	317,534	320,900
Capital Expenditures	'	'	'	'	'	'	'	'	301,697	228,635	58,996
Corporate	'	'	'	'	'	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Assets	464,285,482	'	'	'	638,343,029	'	'	'	464,285,482	638,343,029	600,637,249
Depreciation & Amortization	'	'	'	'	'	'	'	'	3,814,097	1,885,489	1,999,164
Capital Expenditures	'	'	'	'	'	'	'	'	1,057,968	3,634,288	4,740,875
United States | Automotive Products	'	'	'	'	'	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	400,654,021	382,308,501	334,692,637
Germany | Automotive Products	'	'	'	'	'	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	244,949,664	239,081,723	248,495,295
Japan | Automotive Products	'	'	'	'	'	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	123,884,470	100,422,507	76,123,221
Other | Automotive Products	'	'	'	'	'	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	'	'	'	'	$374,499,972	$355,160,210	$343,850,209

Segment_Reporting_Schedule_of_1

Segment Reporting (Schedule of Automotive Customers Individually Accounted For 10% or More of Net Sales) (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue, Major Customer [Line Items]	'	'	'
Percentage net sales invoiced and paid in foreign currencies	7.00%	8.00%	9.00%
Number of customers which individually accounted for 10% or more of net sales	3	'	'
Percentage of net sales five automotive customers individually accounted for	10.00%	'	'
Customer concentration risk | Toyota Motor Corporation	'	'	'
Revenue, Major Customer [Line Items]	'	'	'
Percentage of revenue individually accounted by customers	13.00%	14.00%	12.00%
Customer concentration risk | VW/Audi	'	'	'
Revenue, Major Customer [Line Items]	'	'	'
Percentage of revenue individually accounted by customers	14.00%	14.00%	15.00%
Customer concentration risk | Hyundai/Kia	'	'	'
Revenue, Major Customer [Line Items]	'	'	'
Percentage of revenue individually accounted by customers	'	11.00%	11.00%
Customer concentration risk | Daimler AG	'	'	'
Revenue, Major Customer [Line Items]	'	'	'
Percentage of revenue individually accounted by customers	11.00%	11.00%	11.00%
Customer concentration risk | General Motors	'	'	'
Revenue, Major Customer [Line Items]	'	'	'
Percentage of revenue individually accounted by customers	'	10.00%	12.00%
Maximum | Customer concentration risk | Hyundai/Kia	'	'	'
Revenue, Major Customer [Line Items]	'	'	'
Percentage of revenue individually accounted by customers	'	10.00%	'
Maximum | Customer concentration risk | General Motors	'	'	'
Revenue, Major Customer [Line Items]	'	'	'
Percentage of revenue individually accounted by customers	'	10.00%	'

Quarterly_Financial_Informatio2

Quarterly Financial Information (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Information Disclosure [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Net Sales	$326,770,000	$288,622,000	$286,974,000	$269,499,000	$260,349,000	$268,248,000	$280,256,000	$290,707,000	$1,171,864,171	$1,099,559,521	$1,023,762,049
Gross Profit	128,694,000	105,962,000	102,613,000	93,464,000	89,119,000	90,116,000	92,757,000	100,826,000	430,732,902	372,818,559	361,580,335
Operating Income	95,636,000	73,656,000	71,596,000	63,854,000	53,819,000	57,623,000	57,512,000	65,501,000	304,741,813	234,455,232	231,367,925
Net Income	$69,881,000	$55,521,000	$52,097,000	$45,431,000	$39,599,000	$41,877,000	$40,767,000	$46,345,000	$222,929,949	$168,586,840	$164,668,228
Earnings Per Share (Diluted) (in dollars per share)	$0.48	$0.38	$0.36	$0.32	$0.28	$0.29	$0.28	$0.32	$1.55	$1.17	$1.14
Earnings Per Share (Basic) (in dollars per share)	$0.48	$0.39	$0.36	$0.32	$0.28	$0.29	$0.28	$0.32	$1.55	$1.18	$1.16

Comprehensive_Income_AOCI_Roll

Comprehensive Income (AOCI Rollforward) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Roll Forward]	'	'	'
Balance at beginning of period	$17,570,711	$12,542,203	'
Comprehensive Income	227,334,601	173,615,348	154,893,528
Balance at end of period	21,975,363	17,570,711	12,542,203
Foreign currency translation adjustments:	'	'	'
Accumulated Other Comprehensive Income (Loss) [Roll Forward]	'	'	'
Balance at beginning of period	2,458,933	2,129,957	566,903
Other Comprehensive income before reclassifications	48,989	328,976	1,563,054
Amounts reclassified from accumulated other comprehensive income	0	0	0
Comprehensive Income	48,989	328,976	1,563,054
Balance at end of period	2,507,922	2,458,933	2,129,957
Unrealized gains(losses) on available-for-sale securities:	'	'	'
Accumulated Other Comprehensive Income (Loss) [Roll Forward]	'	'	'
Balance at beginning of period	15,111,778	10,412,246	21,750,000
Other Comprehensive income before reclassifications	16,139,845	10,138,902	-7,012,974
Amounts reclassified from accumulated other comprehensive income	-11,784,182	-5,439,370	-4,324,780
Comprehensive Income	4,355,663	4,699,532	-11,337,754
Balance at end of period	$19,467,441	$15,111,778	$10,412,246

Comprehensive_Income_Reclassif

Comprehensive Income (Reclassification Out of Accumulated Other Comprehensive Income) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]	'	'	'
Provision for Income Taxes	($105,134,094)	($81,038,760)	($79,763,583)
Amounts Reclassified from Other Comprehensive Income | Unrealized gains and (losses) on available-for-sale securities	'	'	'
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]	'	'	'
Realized gain (loss) on sale of securities	18,129,511	8,368,261	6,653,508
Provision for Income Taxes	-6,345,329	-2,928,891	-2,328,728
Total reclassifications for the period	$11,784,182	$5,439,370	$4,324,780

Business_Combinations_Details

Business Combinations (Details) (USD $)

0 Months Ended

3 Months Ended

12 Months Ended

0 Months Ended

3 Months Ended

6 Months Ended

Jul. 18, 2013

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Jul. 18, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

HomeLinkB.

HomeLinkB.

HomeLinkB.

Selling, General and Administrative Expenses

Prepaid Expenses and Other

HomeLinkB.

HomeLinkB.

Business Acquisition [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Purchase price

'

'

'

'

'

'

'

'

'

'

'

'

$700,000,000

'

'

'

'

Minimum term in business

'10 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revenues

'

326,770,000

288,622,000

286,974,000

269,499,000

260,349,000

268,248,000

280,256,000

290,707,000

1,171,864,171

1,099,559,521

1,023,762,049

'

36,900,000

36,900,000

'

'

Gross profit

'

128,694,000

105,962,000

102,613,000

93,464,000

89,119,000

90,116,000

92,757,000

100,826,000

430,732,902

372,818,559

361,580,335

'

20,200,000

20,200,000

'

'

Cash paid to acquire business

'

'

'

'

'

'

'

'

'

'

'

'

423,000,000

'

'

'

'

Acquisition-related costs

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3,300,000

2,300,000

'

Debt issuance cost

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$1,000,000

Business_Combinations_Schedule

Business Combinations (Schedule of Preliminary Allocation of Purchase Price) (Details) (USD $)

12 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Sep. 30, 2013

Sep. 27, 2013

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

HomeLinkB.

HomeLinkB.

HomeLinkB.

HomeLink Trade Names and Trademarks

HomeLink Trade Names and Trademarks

Exclusive Licensing Agreement

Exclusive Licensing Agreement

Homelink Technology

Homelink Technology

Existing Customer Platforms

Existing Customer Platforms

HomeLinkB.

HomeLinkB.

HomeLinkB.

HomeLinkB.

HomeLinkB.

HomeLinkB.

HomeLinkB.

HomeLinkB.

Business Acquisition [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

Prepaid Service Agreement Costs

'

'

$0

$3,383,000

'

'

'

'

'

'

'

'

'

Prepaid Service Agreement Costs, Other Adjustments

'

'

-3,383,000

'

'

'

'

'

'

'

'

'

'

Personal Property

'

'

8,114,600

4,430,986

'

'

'

'

'

'

'

'

'

Personal Property, Fair Value Adjustments

'

'

3,683,614

'

'

'

'

'

'

'

'

'

'

Real Property

'

'

1,060,000

1,060,000

'

'

'

'

'

'

'

'

'

Indefinite-lived intangible assets

'

'

'

'

'

52,000,000

47,000,000

96,000,000

87,000,000

'

'

'

'

Finite-lived intangibles

'

'

'

'

'

'

'

'

'

180,000,000

166,000,000

43,000,000

43,000,000

Intangible Assets, Fair Value Adjustments

'

'

'

'

'

5,000,000

'

9,000,000

'

14,000,000

'

'

'

Accounts Receivable

'

'

11,119,447

7,719,302

'

'

'

'

'

'

'

'

'

Accounts Receivable, Other Adjustments

'

'

3,400,145

'

'

'

'

'

'

'

'

'

'

Net Customer Tooling

'

'

983,406

956,665

'

'

'

'

'

'

'

'

'

Net Customer Tooling, Other Adjustments

'

'

26,741

'

'

'

'

'

'

'

'

'

'

Fair Value of Acquired Assets

'

'

392,277,453

360,549,953

'

'

'

'

'

'

'

'

'

Fair Value of Acquired Assets, Fair Value Adjustments

'

'

31,683,614

'

'

'

'

'

'

'

'

'

'

Fair Value of Acquired Assets, Other Adjustments

'

'

43,886

'

'

'

'

'

'

'

'

'

'

Other adjustments

'

'

-1,492,398

'

'

'

'

'

'

'

'

'

'

Other adjustments, Other Adjustments

'

'

-1,492,398

'

'

'

'

'

'

'

'

'

'

Goodwill

307,365,845

0

307,365,845

337,557,061

337,600,000

'

'

'

'

'

'

'

'

Goodwill, Fair Value Adjustments

0

'

31,683,614

'

'

'

'

'

'

'

'

'

'

Goodwill, Other Adjustments

'

'

-1,492,398

'

'

'

'

'

'

'

'

'

'

Total Cash Consideration

'

'

698,150,900

698,107,014

'

'

'

'

'

'

'

'

'

Total Cash Consideration, Fair Value Adjustments

'

'

0

'

'

'

'

'

'

'

'

'

'

Total Cash Consideration, Other Adjustments

'

'

$43,886

'

'

'

'

'

'

'

'

'

'

Business_Combinations_Pro_Form

Business Combinations (Pro Forma Information) (Details) (HomeLinkB., USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
HomeLinkB.	'	'
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]	'	'
Net Sales	$1,271,320	$1,216,009
Net Income	$253,678	$205,023

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets (Details) (USD $)	12 Months Ended					12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2013	Sep. 30, 2013	Sep. 27, 2013
				Newly acquired and existing patents	Newly acquired and existing patents	Minimum	HomeLinkB.	HomeLinkB.	HomeLinkB.
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]	'	'	'	'	'	'	'	'	'
Goodwill	$307,365,845	$0	'	'	'	'	$307,365,845	$337,557,061	$337,600,000
Goodwill that is expected to be deductible for tax purposes	'	'	'	'	'	'	307,400,000	'	'
Finite-lived intangible asset, useful life	'	'	'	'11 years	'	'10 years	'	'	'
Accumulated amortization	'	'	'	13,400,000	6,100,000	'	4,825,000	'	'
Amortization expense	7,900,000	1,700,000	1,100,000	'	'	'	'	'	'
Amortization expense, 2014	22,000,000	'	'	'	'	'	'	'	'
Amortization expense, 2015	22,000,000	'	'	'	'	'	'	'	'
Amortization expense, 2016	22,000,000	'	'	'	'	'	'	'	'
Amortization expense, 2017	22,000,000	'	'	'	'	'	'	'	'
Amortization expense, 2018	$22,000,000	'	'	'	'	'	'	'	'

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets (Schedule of Goodwill) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013
Goodwill [Roll Forward]	'
Balance as of December 31, 2012	$0
Acquisitions	307,365,845
Divestitures	0
Impairments	0
Other	0
Balance as of December 31, 2013	$307,365,845

Goodwill_and_Other_Intangible_4

Goodwill and Other Intangible Assets (Schedule of Intangible Assets) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
			Minimum	HomeLinkB.	HomeLinkB.	HomeLinkB.	HomeLinkB.	HomeLinkB.	HomeLinkB.
					Homelink Technology	Homelink Technology	Existing Customer Platforms	HomeLink Trade Names and Trademarks	Exclusive Licensing Agreement
						Minimum
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]	'	'	'	'	'	'	'	'	'
Indefinite-lived intangible assets	'	'	'	'	'	'	'	$52,000,000	$96,000,000
Finite-lived intangible assets, gross	'	'	'	'	180,000,000	'	43,000,000	'	'
Finite-lived intangible assets, accumulated amortization	'	'	'	-4,825,000	-3,750,000	'	-1,075,000	'	'
Finite-lived intangible assets, net	'	'	'	'	176,250,000	'	41,925,000	'	'
Intangible assets, gross	'	'	'	371,000,000	'	'	'	'	'
Intangible assets, net	$366,175,000	$0	'	$366,175,000	'	'	'	'	'
Finite-lived intangible asset, useful life	'	'	'10 years	'	'	'12 years	'10 years	'	'