Employee Benefits - Accumulated Other Comprehensive Income (Loss) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]
Prior service credit	$ (1,167)	$ (1,304)
Net actuarial loss	30,726	18,373
Total (Before Tax Effects)	$ 29,559	$ 17,069

Other comprehensive income loss qualified pension plan adjustment before tax.

No definition available.

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- Details

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- Definition

Amount before tax, after reclassification adjustments, of actuarial gain (loss) that has not been recognized in the income statement.

+ 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 (i)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 10A

-Subparagraph (i)

-URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669646-108580

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- Definition

Amount before tax, after reclassification adjustments, of prior service cost (credit) that has not been recognized in the income statement.

+ 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 (i)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 10A

-Subparagraph (j)

-URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669646-108580

+ Details

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