Retirement Plans - Expected Benefit Payments to Participants and Estimated Contributions to be Made by Company (Detail) $ in Thousands	Dec. 31, 2018 USD ($)
Retirement Benefits [Abstract]
Expected Benefit Payments to Participants, 2019	$ 1,254
Expected Benefit Payments to Participants, 2020	1,668
Expected Benefit Payments to Participants, 2021	2,192
Expected Benefit Payments to Participants, 2022	2,161
Expected Benefit Payments to Participants, 2023	2,153
Expected Benefit Payments to Participants, 2024-2028	10,928
Estimated Company Contributions, 2019	1,254
Estimated Company Contributions, 2020	1,668
Estimated Company Contributions, 2021	2,192
Estimated Company Contributions, 2022	2,161
Estimated Company Contributions, 2023	2,153
Estimated Company Contributions, 2024-2028	$ 10,928

Defined benefit plan estimated future employer contributions five fiscal years thereafter.

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- Definition

Defined benefit plan estimated future employer contributions in year five.

+ References

No definition available.

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- Definition

Defined benefit plan estimated future employer contributions in year four.

+ References

No definition available.

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- Definition

Defined benefit plan estimated future employer contributions in year three.

+ References

No definition available.

+ Details

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- Definition

Defined benefit plan estimated future employer contributions in year two.

+ References

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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

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- Definition

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

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- Definition

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

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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.

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- Definition

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

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- Definition

Amount of contributions expected to be received by defined benefit plan from employer in next fiscal year following latest fiscal year.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

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