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Benefit Plans - Weighted Average Assumptions Used to Determine Benefit Obligation (Detail) - Defined Benefit Pension Plan [Member]	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Weighted Average Assumptions Used to Determine Benefit Obligation
Discount rate used for disclosure	0.00%	0.00%
First five years	1.47%	4.25%
Five years to twenty years	3.34%	4.25%
After twenty years	4.30%	4.25%
Expected return on plan assets	7.50%	7.50%
Rate of compensation increase	3.00%	3.00%

X

- Definition

Defined benefit plan assumptions used calculating benefit obligation discount rate after twenty years.

+ References

No definition available.

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- Definition

Defined benefit plan assumptions used calculating benefit obligation discount rate first five years.

+ References

No definition available.

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- Definition

Defined benefit plan assumptions used calculating benefit obligation discount rate five year to twenty years.

+ References

No definition available.

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X

- Definition

The interest rate used to adjust for the time value of money for the plan.

+ 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 (k)(1)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

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X

- Definition

Expected rate of compensation increases (for pay-related plans).

+ 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 (k)(2)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

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X

- Definition

An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Expected Long-Term Rate of Return on Plan Assets
-URI http://asc.fasb.org/extlink&oid=6512046

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(3)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

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- References

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