Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

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The net result for the period of deducting operating expenses from operating revenues.

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The cash outflow for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets.

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Aggregate revenue during the period from the sale of goods in the normal course of business, after deducting returns, allowances and discounts.

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Segment Reporting (Schedule of Automotive and Other Segment Reporting) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Revenues	$ 350,411,000us-gaap_SalesRevenueGoodsNet	$ 350,914,000us-gaap_SalesRevenueGoodsNet	$ 338,437,000us-gaap_SalesRevenueGoodsNet	$ 335,739,000us-gaap_SalesRevenueGoodsNet	$ 326,770,000us-gaap_SalesRevenueGoodsNet	$ 288,622,000us-gaap_SalesRevenueGoodsNet	$ 286,974,000us-gaap_SalesRevenueGoodsNet	$ 269,499,000us-gaap_SalesRevenueGoodsNet	$ 1,375,501,159us-gaap_SalesRevenueGoodsNet	$ 1,171,864,171us-gaap_SalesRevenueGoodsNet	$ 1,099,559,521us-gaap_SalesRevenueGoodsNet
Income (Loss) from Operations	98,615,000us-gaap_OperatingIncomeLoss	103,206,000us-gaap_OperatingIncomeLoss	99,835,000us-gaap_OperatingIncomeLoss	97,178,000us-gaap_OperatingIncomeLoss	95,636,000us-gaap_OperatingIncomeLoss	73,656,000us-gaap_OperatingIncomeLoss	71,596,000us-gaap_OperatingIncomeLoss	63,854,000us-gaap_OperatingIncomeLoss	398,834,174us-gaap_OperatingIncomeLoss	304,741,813us-gaap_OperatingIncomeLoss	234,455,232us-gaap_OperatingIncomeLoss
Assets	2,022,540,029us-gaap_Assets				1,764,088,434us-gaap_Assets				2,022,540,029us-gaap_Assets	1,764,088,434us-gaap_Assets	1,265,691,335us-gaap_Assets
Depreciation & Amortization									77,376,305	62,854,155	50,179,823
Capital Expenditures									72,518,987	55,380,457	117,474,449
Automotive Products
Segment Reporting Information [Line Items]
Income (Loss) from Operations									386,762,986	298,465,299	231,713,972
Assets	1,333,615,389				1,290,801,674				1,333,615,389	1,290,801,674	619,337,527
Depreciation & Amortization									75,320,999	58,723,222	47,976,800
Capital Expenditures									71,032,115	54,020,792	113,611,526
Other
Segment Reporting Information [Line Items]
Revenues									35,378,885	27,876,044	22,586,580
Income (Loss) from Operations									12,071,188	6,276,514	2,741,260
Assets	8,841,958				9,001,278				8,841,958	9,001,278	8,010,779
Depreciation & Amortization									321,426	316,836	317,534
Capital Expenditures									145,704	301,697	228,635
Corporate
Segment Reporting Information [Line Items]
Assets	680,082,682				464,285,482				680,082,682	464,285,482	638,343,029
Depreciation & Amortization									1,733,880	3,814,097	1,885,489
Capital Expenditures									1,341,168	1,057,968	3,634,288
United States \| Automotive Products
Segment Reporting Information [Line Items]
Revenues									444,921,897	400,654,021	382,308,501
Germany \| Automotive Products
Segment Reporting Information [Line Items]
Revenues									262,505,346	244,949,664	239,081,723
Japan \| Automotive Products
Segment Reporting Information [Line Items]
Revenues									133,758,799	123,884,470	100,422,507
Other \| Automotive Products
Segment Reporting Information [Line Items]
Revenues									$ 498,936,232	$ 374,499,972	$ 355,160,210