Commitments and Contingencies (details) (USD $)	6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011
Accrual For Environmental Loss Contingencies [Abstract]
Other current liabilities	$ 42,336,000	$ 41,597,000	$ 37,574,000
Other non-current liabilities	82,665,000	76,265,000	70,127,000
Environmental Remediation Obligations Abstract
Portland Harbor draft FS range	$169 million to $1.8 billion
Portland Harbor Number Of Potentially Responsible Parties	more than 100
Gasco Siltronic Sediments draft EE/CA range	$34 million and $350 million
Gasco Siltronic Sediments Project Liability	34,000,000
Gasco Siltronic Sediments Other Liability	11,400,000
Portland Harbor RIFS And NRD Liability	4,700,000
Gasco Upland Liability	8,600,000
Gasco Groundwater Source Control range	$14 million and $30 million
Gasco Source Control Liability	14,800,000
Wutc Environmental Deferral Start Date	January 26, 2011
Cumulative Environmental Costs Recognized	133,400,000
Cumulative Environmental Costs Recognized Prior To Regulatory Order	4,900,000
Environmental Regulatory Assets Noncurrent	117,900,000
Environmental Insurance Recovery	50,000,000
Environmental Current Liabilities	17,665,000	20,183,000	13,595,000
Environmental Noncurrent Liabilities	59,063,000	52,506,000	45,960,000
Gasco Siltronic Sediments [Member]
Accrual For Environmental Loss Contingencies [Abstract]
Other current liabilities	2,340,000	1,614,000	995,000
Other non-current liabilities	43,066,000	35,797,000	29,866,000
Portland Harbor Other [Member]
Accrual For Environmental Loss Contingencies [Abstract]
Other current liabilities	1,286,000	1,893,000	2,619,000
Other non-current liabilities	3,409,000	7,066,000	5,426,000
Gasco [Member]
Accrual For Environmental Loss Contingencies [Abstract]
Other current liabilities	12,606,000	14,092,000	9,140,000
Other non-current liabilities	10,769,000	8,900,000	9,099,000
Siltronic Upland [Member]
Accrual For Environmental Loss Contingencies [Abstract]
Other current liabilities	467,000	887,000	836,000
Other non-current liabilities	620,000	128,000	71,000
Other Liabilities	1,100,000
Central Service Center [Member]
Accrual For Environmental Loss Contingencies [Abstract]
Other current liabilities	100,000	0	5,000
Other non-current liabilities	436,000	495,000	543,000
Other Liabilities	500,000
Front Street [Member]
Accrual For Environmental Loss Contingencies [Abstract]
Other current liabilities	866,000	1,697,000	0
Other non-current liabilities	646,000	0	823,000
Other Liabilities	1,500,000
Other Environmental [Member]
Accrual For Environmental Loss Contingencies [Abstract]
Other current liabilities	0	0	0
Other non-current liabilities	$ 117,000	$ 120,000	$ 132,000