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Commitments and Contingencies - Additional Information (Detail) (USD $) | 1 Months Ended |  | 6 Months Ended
--- | --- | --- | ---
Jun. 30, 2007 | Jun. 30, 2014 Parties | Jun. 30, 2014 Portland Harbor Natural Resources Trustee Council [Member] | Jun. 30, 2014 Minimum [Member] | Jun. 30, 2014 Maximum [Member]
Other Commitments [Line Items] |  |  |  |  |
Company made payment to Lower Willamette Group as interim settlement | $ 175,000 |  |  |  |
Estimated cost |  |  |  | 169,000,000 | 1,760,000,000
Estimated years to implement |  |  |  | 2 years | 28 years
Amount anticipated to spent for further Source Control work |  | 100,000 |  |  |
Accrued funding for injury assessment process |  |  | 360,000 |  |
Number of potentially responsible parties |  | 100 |  |  |
Total stand-by letters of credit |  | $ 3,100,000 |  |  |

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- Definition Amount of payments made reducing loss contingency liability. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349 + Details
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