Amount of contributions made by the employer to defined benefit plans.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of the employer's best estimate of contributions expected to be paid to the plan in the current fiscal period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 6
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- Definition

Amount of net gain (loss) recognized in net periodic benefit cost due to settlements and curtailments. Curtailments result from an event that significantly reduces the expected years of future service of present employees or eliminates for a significant number of employees the accrual of defined benefits for some or all of their future services. Settlements result from an irrevocable action that relieves the employer (or the plan) of primary responsibility for a benefit obligation and eliminates significant risks related to the obligation and the assets used to effect the settlement. Examples of transactions that constitute a settlement include, but are not limited to, lump-sum cash payments to plan participants in exchange for their rights to receive specified benefits and purchasing nonparticipating annuity contracts to cover vested benefits.

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- Definition

Amount of employer's best estimate of contributions expected to be paid to the plan during the next fiscal year beginning after the date of the latest statement of financial position.

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Retirement Benefits (Additional Information) (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer		$ 4.5
Forecast \| Minimum
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	$ 8.0
Loss due to settlements	3.0
Forecast \| Maximum
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	10.0
Loss due to settlements	$ 6.0
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Expected contribution for next fiscal year			$ 6.1
Expected contributions in current fiscal year		4.5
Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Expected contribution for next fiscal year			$ 0.9
Expected contributions in current fiscal year		$ 0.9