Items to be Recognized in 2015 as Component of Net Periodic Cost (Detail) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Items to be recognized in 2015 as a component of net periodic cost
Accumulated benefit obligation, pension benefit plans	$ 720,200,000	$ 606,100,000
Foreign Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligations in excess of plan assets, projected benefit obligation	77,400,000	61,100,000
Items to be recognized in 2015 as a component of net periodic cost
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Accumulated Benefit Obligation	71,100,000	56,500,000
Pension Benefits [Member]
Items to be recognized in 2015 as a component of net periodic cost
Net actuarial loss (gain)	7,354,000
Prior service cost (credit)	1,028,000
Net periodic cost (credit) to be recorded in 2015	8,382,000
Other Postretirement Benefits [Member]
Items to be recognized in 2015 as a component of net periodic cost
Net actuarial loss (gain)	(254,000)
Prior service cost (credit)	(2,942,000)
Net periodic cost (credit) to be recorded in 2015	$ (3,196,000)

For defined benefit pension plans, the actuarial present value of benefits (whether vested or nonvested) attributed by the pension benefit formula to employee service rendered before a specified date and based on employee service and compensation (if applicable) before that date. The accumulated benefit obligation differs from the projected benefit obligation in that it includes no assumption about future compensation levels. For plans with flat-benefit or nonpay-related pension benefit formulas, the accumulated benefit obligation and the projected benefit obligation are the same.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Accumulated Benefit Obligation

-URI http://asc.fasb.org/extlink&oid=6503844

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (e)

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

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- Definition

Amount included in accumulated other comprehensive income (AOCI) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position, including gain (loss), prior service cost (credit), and transition asset (obligation).

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- Definition

If aggregate disclosures are presented, the aggregate pension accumulated benefit obligation for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 55

-Paragraph 17

-URI http://asc.fasb.org/extlink&oid=34716465&loc=d3e4179-114921

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e2417-114920

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If aggregate disclosures are presented, the aggregate projected benefit obligation for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

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