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Retirement Plans and Other Post-Retirement Benefits - Schedule of Target Allocation for Plan Assets (Detail)	12 Months Ended
	Dec. 31, 2015
Large Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation for the plan assets	35.00%
Small and Mid Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation for the plan assets	12.00%
International Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation for the plan assets	13.00%
Real Estate Investment Trusts (REIT) [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation for the plan assets	5.00%
Fixed Income, Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation for the plan assets	35.00%

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Target allocation of investments of this type to total plan assets presented on a weighted average basis.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (c)(i)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2446-114920

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

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