Employee Retirement and Profit Sharing Plans - Reconciliation of Change in Fair Value Measurement of Defined Benefit Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Change in plan assets:
Fair value of plan assets at beginning of year	$ 282,183
Fair value of plan assets at end of year	344,760	$ 282,183
Diversified Funds
Change in plan assets:
Fair value of plan assets at beginning of year	3,930
Fair value of plan assets at end of year	2,700	3,930
Partnerships/ Joint Ventures
Change in plan assets:
Fair value of plan assets at beginning of year	163
Fair value of plan assets at end of year		163
Level 3
Change in plan assets:
Fair value of plan assets at beginning of year	4,093	4,202
Relating to instruments still held at reporting date	97	97
Relating to instruments sold during the period	(1)
Purchases, sales and settlements (net)	(1,849)	(206)
Transfers in and/or out of Level 3	360
Fair value of plan assets at end of year	2,700	4,093
Level 3 \| Diversified Funds
Change in plan assets:
Fair value of plan assets at beginning of year	3,930	3,929
Relating to instruments still held at reporting date	97	115
Relating to instruments sold during the period	0
Purchases, sales and settlements (net)	(1,849)	(114)
Transfers in and/or out of Level 3	522
Fair value of plan assets at end of year	2,700	3,930
Level 3 \| Partnerships/ Joint Ventures
Change in plan assets:
Fair value of plan assets at beginning of year	163	273
Relating to instruments still held at reporting date	0	(18)
Relating to instruments sold during the period	(1)
Purchases, sales and settlements (net)	0	(92)
Transfers in and/or out of Level 3	(162)
Fair value of plan assets at end of year	$ 0	$ 163

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan from actual return (loss) on assets sold.

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)(5)(iv)(02)(A)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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- Definition

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan from actual return (loss) on assets still held.

+ References

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees.

+ 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 (b)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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- Definition

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan from purchases, sales and settlements.

+ 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)(5)(iv)(02)(B)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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- Definition

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan, for assets transferred into (out of) Level 3 of fair value hierarchy. Includes, but is not limited to, transfer due to change in observability of significant inputs.

+ 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)(5)(iv)(02)(C)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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