Environmental Matters (details) (USD $)	3 Months Ended
	Mar. 31, 2014		Dec. 31, 2013		Mar. 31, 2013
Accrual for Environmental Loss Contingencies [Abstract]
Environmental Noncurrent Liabilities	$ 82,261,000		$ 81,895,000		$ 50,386,000
Environmental Current Liabilities	13,068,000		16,176,000		18,874,000
Environmental Regulatory Table [Abstract]
Cash Paid for Environmental Sites	106,105,000	[1]	98,817,000	[1]	75,620,000	[1]
Regulatory Assets, Noncurrent	285,046,000		369,603,000		384,453,000
Environmental Remediation Obligations [Abstract]
Damages Sought On Environmental Claims	50,000,000
Environmental Settlement Insurance Payments Expected in 2014	102,000,000
Environmental Settlement Payments Received To Date	91,000,000
Environmental settlement payments expected	11,000,000
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	$39.4 million to $350 million
Gasco Siltronic Sediments Project Liability	39,400,000.0
Gasco Groundwater Source Control construction costs	19,000,000
Gasco Groundwater Source Control Allocated Insurance Proceeds To Constructed Water Treatment Station	2,500,000
Gasco Siltronic Sediments [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Environmental Noncurrent Liabilities	38,584,000		37,954,000		38,050,000
Environmental Current Liabilities	776,000		1,278,000		389,000
Portland Harbor Other [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Environmental Noncurrent Liabilities	3,283,000		3,478,000		2,793,000
Environmental Current Liabilities	1,408,000		1,766,000		1,678,000
Gasco Upland [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Environmental Noncurrent Liabilities	39,482,000		39,508,000		8,365,000
Environmental Current Liabilities	8,766,000		11,010,000		15,411,000
Siltronic Upland [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Environmental Noncurrent Liabilities	394,000		406,000		414,000
Environmental Current Liabilities	872,000		763,000		556,000
Central Service Center [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Environmental Noncurrent Liabilities	224,000		248,000		386,000
Environmental Current Liabilities	70,000		85,000		80,000
Front Street [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Environmental Noncurrent Liabilities	115,000		122,000		199,000
Environmental Current Liabilities	1,176,000		1,274,000		760,000
Oregon Steel Mills [Member]
Accrual for Environmental Loss Contingencies [Abstract]
Environmental Noncurrent Liabilities	179,000		179,000		179,000
Environmental Current Liabilities	0		0		0
Environmental Restoration Costs [Member]
Environmental Regulatory Table [Abstract]
Regulatory Assets, Noncurrent	$ 63,517,000	[2],[3]	$ 148,389,000	[2],[3]	$ 125,671,000	[2],[3]

[1] Includes $20.1 million reclassified to utility plant in 2013 associated with the water treatment station of which a portion was paid in 2012.

[2] Includes cash paid, remaining liability, and interest, net of insurance reimbursement and amounts reclassified to utility plant for the water treatment station.

[3] Environmental costs relate to specific sites approved for regulatory deferral by the Public Utility Commission of Oregon (OPUC) and Washington Utilities and Transportation Commission (WUTC). In Oregon, we earn a carrying charge on cash amounts paid, whereas amounts accrued but not yet paid do not earn a carrying charge until expended. In Washington, a carrying charge related to deferred amounts will be determined in a future proceeding. For further information on environmental matters, see Note 13.