Segment Information (Financial Information Related To The Company's Business Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenues	$ 200,520us-gaap_RevenueMineralSales	$ 219,499us-gaap_RevenueMineralSales
Depletion, depreciation and amortization	17,121	15,151
General and administrative expenses	8,345us-gaap_GeneralAndAdministrativeExpense	9,786us-gaap_GeneralAndAdministrativeExpense
Interest income	703us-gaap_InvestmentIncomeInterest	825us-gaap_InvestmentIncomeInterest
Interest expense	5,304us-gaap_InterestAndDebtExpense	5,850us-gaap_InterestAndDebtExpense
Income (loss) before income taxes		24,164
Income (loss) before income taxes	16,845	24,164
Capital expenditures	27,902	26,133
Total assets	1,409,043us-gaap_Assets	1,358,850us-gaap_Assets	1,399,327us-gaap_Assets
Mine Production [Member]
Segment Reporting Information [Line Items]
Revenues	125,738	125,729
Depletion, depreciation and amortization	16,869	14,910
General and administrative expenses	0	0
Interest income	0	0
Interest expense	0	0
Income (loss) before income taxes		32,827
Income (loss) before income taxes	28,828
Capital expenditures	25,548	24,861
Total assets	607,117	567,505
PGM Recycling [Member]
Segment Reporting Information [Line Items]
Revenues	74,682	93,535
Depletion, depreciation and amortization	252	241
General and administrative expenses	0	0
Interest income	403	579
Interest expense	0	0
Income (loss) before income taxes		3,168
Income (loss) before income taxes	2,127
Capital expenditures	59	113
Total assets	57,740	88,931
Canadian Properties [Member]
Segment Reporting Information [Line Items]
Revenues	0	0
Depletion, depreciation and amortization	0	0
General and administrative expenses	235	1,656
Interest income	3	2
Interest expense	0	0
Income (loss) before income taxes		(1,890)
Income (loss) before income taxes	(433)
Capital expenditures	0	0
Total assets	74,734	79,856
South American Properties [Member]
Segment Reporting Information [Line Items]
Revenues	0	0
Depletion, depreciation and amortization	0	0
General and administrative expenses	182	200
Interest income	14	16
Interest expense	0	0
Income (loss) before income taxes		3,185
Income (loss) before income taxes	(773)
Capital expenditures	0	0
Total assets	105,795	108,839
All Other [Member]
Segment Reporting Information [Line Items]
Revenues	100	235
Depletion, depreciation and amortization	0	0
General and administrative expenses	7,928	7,930
Interest income	283	228
Interest expense	5,304	5,850
Income (loss) before income taxes		(13,126)
Income (loss) before income taxes	(12,904)
Capital expenditures	2,295	1,159
Total assets	$ 563,657	$ 513,719

Income (Loss) from Continuing Operations before Impairment Charge, Equity Method Investments, Income Taxes,

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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 aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

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Sum of operating profit and nonoperating income or expense before Income or Loss from equity method investments, income taxes, extraordinary items, and noncontrolling interest.

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Interest and debt related expenses associated with nonoperating financing activities of the entity.

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Amount before accretion (amortization) of purchase discount (premium) of interest income on nonoperating securities.

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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 from the sale of minerals and related products, and from rendering services such as exploration, development, mining, processing and providing mining support activities.

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