Postretirement Benefit Plans - Estimated Future Benefit Payments (Detail) $ in Thousands	Dec. 31, 2017 USD ($)
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
2018	$ 7,560
2019	7,956
2020	8,438
2021	8,973
2022	9,448
2023-2027	51,168
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
2018	504
2019	511
2020	516
2021	539
2022	585
2023-2027	$ 3,548

Pension plans postretirement and other employee benefits.

No definition available.

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- Definition

Amount of benefits for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following latest fiscal year.

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

+ Details

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- Definition

Amount of benefits for defined benefit plan expected to be paid in next fiscal year following latest fiscal year.

+ References

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- Definition

Amount of benefits for defined benefit plan expected to be paid in fifth fiscal year following latest fiscal year.

+ References

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- Definition

Amount of benefits for defined benefit plan expected to be paid in fourth fiscal year following latest fiscal year.

+ References

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- Definition

Amount of benefits for defined benefit plan expected to be paid in third fiscal year following latest fiscal year.

+ References

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- Definition

Amount of benefits for defined benefit plan expected to be paid in second fiscal year following latest fiscal year.

+ References

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