Segment Information (Financial Information Related To The Company's Business Segments) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Revenues	$ 168,441	$ 252,066	$ 554,345	$ 721,452
Depletion, depreciation and amortization	15,362	17,181	49,681	50,134
General and administrative expenses	8,911	10,051	27,652	28,017
Interest income	766	931	2,192	2,750
Interest expense	5,097	6,018	15,713	17,737
Income (loss) before impairment charge and income taxes			10,485
Impairment charge	0	0	46,772	0
(LOSS) INCOME BEFORE INCOME TAX BENEFIT (PROVISION)	(14,493)	23,454	(36,287)	70,441
Capital expenditures	25,168	33,258	83,386	87,038
Total assets	1,317,187	1,384,459	1,317,187	1,384,459	$ 1,399,327
Cash and cash equivalents	133,956	257,617	133,956	257,617	$ 280,286	$ 286,687
Mine Production [Member] | Business Segments [Member]
Segment Reporting Information [Line Items]
Revenues	86,359	137,067	331,065	409,967
Depletion, depreciation and amortization	15,132	16,923	48,943	49,373
General and administrative expenses	0	0	0	0
Interest income	0	0	0	0
Interest expense	0	0	0	0
Income (loss) before impairment charge and income taxes			52,446
Impairment charge			0
(LOSS) INCOME BEFORE INCOME TAX BENEFIT (PROVISION)	2,224	34,904	52,446	107,864
Capital expenditures	24,661	32,604	77,370	84,335
Total assets	608,198	584,538	608,198	584,538
PGM Recycling [Member] | Business Segments [Member]
Segment Reporting Information [Line Items]
Revenues	81,982	109,509	222,980	305,760
Depletion, depreciation and amortization	230	258	738	761
General and administrative expenses	0	0	0	0
Interest income	437	681	1,256	1,998
Interest expense	0	0	0	0
Income (loss) before impairment charge and income taxes			7,424
Impairment charge			0
(LOSS) INCOME BEFORE INCOME TAX BENEFIT (PROVISION)	3,261	3,131	7,424	9,225
Capital expenditures	57	28	221	155
Total assets	3,390	88,411	3,390	88,411
Canadian Properties [Member] | Business Segments [Member]
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Depletion, depreciation and amortization	0	0	0	0
General and administrative expenses	275	794	790	2,783
Interest income	1	1	7	3
Interest expense	0	0	0	0
Income (loss) before impairment charge and income taxes			(1,364)
Impairment charge			46,772
(LOSS) INCOME BEFORE INCOME TAX BENEFIT (PROVISION)	(577)	(1,205)	(48,136)	(3,843)
Capital expenditures	0	0	0	0
Total assets	27,078	76,678	27,078	76,678
Cash and cash equivalents	17,100		17,100
South American Properties [Member] | Business Segments [Member]
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Depletion, depreciation and amortization	0	0	0	0
General and administrative expenses	100	17	454	339
Interest income	4	13	23	44
Interest expense	0	0	0	0
Income (loss) before impairment charge and income taxes			(1,216)
Impairment charge			0
(LOSS) INCOME BEFORE INCOME TAX BENEFIT (PROVISION)	(339)	748	(1,216)	2,841
Capital expenditures	0	2	46	2
Total assets	104,265	107,909	104,265	107,909
All Other [Member] | Business Segments [Member]
Segment Reporting Information [Line Items]
Revenues	100	5,490	300	5,725
Depletion, depreciation and amortization	0	0	0	0
General and administrative expenses	8,536	9,240	26,408	24,895
Interest income	324	236	906	705
Interest expense	5,097	6,018	15,713	17,737
Income (loss) before impairment charge and income taxes			(46,805)
Impairment charge			0
(LOSS) INCOME BEFORE INCOME TAX BENEFIT (PROVISION)	(19,062)	(14,124)	(46,805)	(45,646)
Capital expenditures	450	624	5,749	2,546
Total assets	$ 574,256	$ 526,923	$ 574,256	$ 526,923