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Retirement Plans and Other Post-Retirement Benefits - Schedule of Targeted Range of Investment Allocations of Plan Assets (Detail) | 12 Months Ended
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Dec. 31, 2016
Domestic Equity [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Target allocation for the plan assets, minimum | 35.00%
Target allocation for the plan assets, maximum | 45.00%
International Equity [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Target allocation for the plan assets, minimum | 8.00%
Target allocation for the plan assets, maximum | 14.00%
Real Estate Investment Trusts (REIT) [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Target allocation for the plan assets, minimum | 2.00%
Target allocation for the plan assets, maximum | 6.00%
Fixed Income, Cash and Cash Equivalents [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Target allocation for the plan assets, minimum | 55.00%
Target allocation for the plan assets, maximum | 35.00%

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- Definition Target allocation maximum percentage 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=65897934&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=65897934&loc=d3e1928-114920 + Details
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- Definition Target allocation minimum percentage 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 1 -Subparagraph (d)(i) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920 Reference 2: 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=65897934&loc=d3e2446-114920 + Details
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