Retirement Plans - Expected Annual Benefit Payments (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Pension plan
Expected annual benefit payments based on actuarial estimates:
2018	$ 200
2019	268
2020	278
2021	291
2022	294
Thereafter	2,327
SERP
Expected annual benefit payments based on actuarial estimates:
2018	526
2019	492
2020	487
2021	481
2022	475
Thereafter	$ 2,497

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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

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

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

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

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

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