Employee Benefits (Detail) - Assumptions Used in Computation of Net Periodic Pension Expense	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Weighted-average discount rate	1.78%	2.19%	2.15%
Average compensation increase	2.67%	2.66%	2.65%

Expected rate of compensation increases (for pay-related plans).

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)(2)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

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