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Pension and Savings Plans (Details 3) - Pension Plan [Member]	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Weighted-average assumptions used to determine benefit obligations
Discount rate		4.15%	4.55%
Measurement date		Dec. 31, 2016	Dec. 31, 2015
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate		4.55%	4.15%	4.95%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets	5.90%	6.00%	6.25%	6.85%
Measurement date		December 31, 2015	December 31, 2014	December 31, 2013

X

- Definition

Measurement date at which the weighted-average assumptions are used to determine the benefit obligations as of the end of each year.

+ References

No definition available.

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X

- Definition

The interest rate used to adjust for the time value of money for the plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(1)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

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- Definition

The measurement date for determining rate assumptions used in calculating the net periodic benefit cost (such as the weighted-average expected long-term rate of return on plan assets and the discount rate) is normally the beginning of the year measurement date. If an assumed rate(s) changes due to a subsequent interim measurement of both plan assets and obligations, disclosure of the beginning and more recently assumed rate(s), or a properly weighted combination of the two. Disclosure may include the more recent measurement date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2919-114920

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- Definition

The interest rate used to adjust for the time value of money.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(1)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

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- Definition

An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Expected Long-Term Rate of Return on Plan Assets
-URI http://asc.fasb.org/extlink&oid=6512046

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(3)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

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- References

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