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Employee Benefit Plans - Summary of Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost (Detail)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Pension Plan [Member]
Weighted-average assumptions used to determine Net Periodic Benefit Cost
Discount rate		1.80%
Expected return on plan assets		0.00%
Corridor		10.00%
Supplemental Employee Retirement Plan [Member]
Weighted-average assumptions used to determine Net Periodic Benefit Cost
Discount rate	4.00%	3.35%
Corridor	10.00%	10.00%
Average future working lifetime	6 years 5 months 15 days
Mortality table	RP-2014
Mortality improvement scale	MP-2018

X

- Definition

Defined benefit plan assumptions used calculating net periodic benefit cost corridor.

+ References

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- Definition

Defined benefit plan weighted average assumptions for determining periodic net benefits costs average future working life time.

+ References

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- Definition

Defined benefit plan weighted average assumptions for determining periodic net benefits costs description of mortality.

+ References

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- Definition

Defined benefit plan weighted average assumptions for determining periodic net benefits costs description of mortality improvement scale.

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- Definition

Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan.

+ 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 (k)(1)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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X

- Definition

Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan.

+ 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 (k)(3)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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