Employee Benefit Plans - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Benefit Plans [Line Items]
Profit Sharing and Retirement Savings Plan, plan expense	$ 110.1	$ 71.7	$ 77.7
Unfunded obligation	14.1	9.9
Benefit (expense) associated with early retiree medical plan	$ 0.6	$ 0.6	$ 1.9
Discount rate used to calculate expenses	3.80%	4.60%	3.70%
Health care cost trend rate	6.50%	6.60%	6.60%
Year that trend rate is projected to reach ultimate rate	2027
December 31, 2027 [Member]
Employee Benefit Plans [Line Items]
Health care cost trend rate	4.50%

Early retiree medical plan benefit (expense).

No definition available.

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- Details

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- Definition

Costs and payments related to employee profit sharing and retirement savings plans.

+ References

No definition available.

+ Details

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- Definition

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

+ References

+ Details

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- Definition

1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date.

+ 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 (a)

-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

-Glossary Projected Benefit Obligation

-URI http://asc.fasb.org/extlink&oid=6522206

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Accumulated Postretirement Benefit Obligation

-URI http://asc.fasb.org/extlink&oid=6503904

+ Details

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- Definition

The ultimate trend rate for health care costs.

+ References

+ Details

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- Definition

Year the ultimate health care cost trend rate is expected to be reached, in CCYY format.

+ References

+ Details

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