Employee Benefit Plans Weighted Average Asset Allocations by Asset Category (Detail)	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items]
Actual Asset Allocation As of December 31	100.00%	100.00%
Target Asset Allocation	100.00%
Equity securities
Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items]
Actual Asset Allocation As of December 31	31.00%	32.00%
Target Asset Allocation	31.00%
Debt securities
Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items]
Actual Asset Allocation As of December 31	43.00%	41.00%
Target Asset Allocation	47.00%
Insurance (annuity) contracts
Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items]
Actual Asset Allocation As of December 31	16.00%	17.00%
Target Asset Allocation	16.00%
Real estate
Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items]
Actual Asset Allocation As of December 31	6.00%	5.00%
Target Asset Allocation	3.00%
Other
Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items]
Actual Asset Allocation As of December 31	4.00%	5.00%
Target Asset Allocation	3.00%

Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items]

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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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- Definition

Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held.

+ 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)
-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)(1)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

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