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Commitments and Contingencies - Additional Information (Detail) (USD $)	1 Months Ended			3 Months Ended
	Jun. 30, 2007	Mar. 31, 2014 Parties	Mar. 31, 2014 Portland Harbor Natural Resources Trustee Council [Member]	Mar. 31, 2014 Minimum [Member]	Mar. 31, 2014 Maximum [Member]
Other Commitments [Line Items]
Company made payment to Lower Willamette Group as interim settlement	$ 175,000
Liability to pay	0		0
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
Number of potentially responsible parties		100
Total stand-by letters of credit		$ 3,100,000

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Number of potentially responsible parties for Portland Harbor Superfund site.

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Aggregate carrying amount of the estimated litigation liability for known or estimated probable loss from litigation, which may include attorneys' fees and other litigation costs.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

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-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349



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-Publisher FASB

-Name Accounting Standards Codification

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