Segment Information (Financial Information Related To The Company's Business Segments) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Revenues	$ 133,638	$ 200,520
Depletion, depreciation and amortization	17,260	17,121
General and administrative expenses	8,297	8,345
Interest income	710	703
Interest expense	4,182	5,304
Income (loss) before income taxes	(10,491)	16,845
Capital expenditures	18,842	27,902
Total assets	1,275,239	1,409,043	$ 1,278,389
Mine Production [Member] | Business Segments [Member]
Segment Reporting Information [Line Items]
Revenues	85,802	125,738
Depletion, depreciation and amortization	17,069	16,869
General and administrative expenses	0	0
Interest income	0	0
Interest expense	0	0
Income (loss) before income taxes	1,291	28,828
Capital expenditures	18,435	25,548
Total assets	621,003	607,117
PGM Recycling [Member] | Business Segments [Member]
Segment Reporting Information [Line Items]
Revenues	47,736	74,682
Depletion, depreciation and amortization	191	252
General and administrative expenses	0	0
Interest income	293	403
Interest expense	0	0
Income (loss) before income taxes	1,793	2,127
Capital expenditures	10	59
Total assets	33,349	57,740
Canadian Properties [Member] | Business Segments [Member]
Segment Reporting Information [Line Items]
Revenues	0	0
Depletion, depreciation and amortization	0	0
General and administrative expenses	136	235
Interest income	0	3
Interest expense	0	0
Income (loss) before income taxes	(168)	(433)
Capital expenditures	0	0
Total assets	26,327	74,734
South American Properties [Member] | Business Segments [Member]
Segment Reporting Information [Line Items]
Revenues	0	0
Depletion, depreciation and amortization	0	0
General and administrative expenses	308	182
Interest income	1	14
Interest expense	0	0
Income (loss) before income taxes	(1,243)	(773)
Capital expenditures	0	0
Total assets	105,749	105,795
All Other [Member] | Business Segments [Member]
Segment Reporting Information [Line Items]
Revenues	100	100
Depletion, depreciation and amortization	0	0
General and administrative expenses	7,853	7,928
Interest income	416	283
Interest expense	4,182	5,304
Income (loss) before income taxes	(12,164)	(12,904)
Capital expenditures	397	2,295
Total assets	$ 488,811	$ 563,657