Income Taxes (Details 5) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011
Tax attribute carryforwards
Regular net operating losses	$ 402,298
Capital losses	90,258
Alternative minimum tax credits	3,645
Foreign tax credits	12,659
United States [Member]
Tax attribute carryforwards
Regular net operating losses	122,388
Capital losses	90,258
Alternative minimum tax credits	3,645
Foreign tax credits	12,659
Australia [Member]
Tax attribute carryforwards
Regular net operating losses	0
Capital losses	0
Alternative minimum tax credits	0
Foreign tax credits	0
Bolivia [Member]
Tax attribute carryforwards
Regular net operating losses	0
Capital losses	0
Alternative minimum tax credits	0
Foreign tax credits	0
Canada [Member]
Tax attribute carryforwards
Regular net operating losses	4,798
Capital losses	0
Alternative minimum tax credits	0
Foreign tax credits	0
Chile [Member]
Tax attribute carryforwards
Regular net operating losses	0
Capital losses	0
Alternative minimum tax credits	0
Foreign tax credits	0
Mexico [Member]
Tax attribute carryforwards
Regular net operating losses	172,532
Capital losses	0
Alternative minimum tax credits	0
Foreign tax credits	0
New Zealand [Member]
Tax attribute carryforwards
Regular net operating losses	96,524
Capital losses	0
Alternative minimum tax credits	0
Foreign tax credits	0
Other [Member]
Tax attribute carryforwards
Regular net operating losses	6,056
Capital losses	0
Alternative minimum tax credits	0
Foreign tax credits	$ 0