Maturity Year of Debt Instrument

No definition available.

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- Definition

Amount of amortization expense attributable to debt issuance costs.

+ References

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-Publisher FASB
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-Topic 230
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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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- Definition

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.

+ References

No definition available.

+ Details

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
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+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

+ References

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- Details

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- Details

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Financing (Components Of Debt) (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2017	Dec. 31, 2018
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	5.00%
Long-term debt	$ 940.2		$ 942.3
Short-term Debt	$ 63.1		$ 6.9
Four Point Four Five Percent Notes Due Two Thousand And Twenty Three [Member]
Debt Instrument [Line Items]
Maturity Year Of Debt Instrument	2023
Debt Instrument, Interest Rate, Stated Percentage	4.45%		4.45%
Six Point Five Five Percent Notes Due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 198.2		$ 198.2
Four Point Four Five Percent Notes Due 2023 [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 298.7		$ 298.6
6.55% Notes Due 2036
Debt Instrument [Line Items]
Maturity Year Of Debt Instrument	2036
Debt Instrument, Interest Rate, Stated Percentage	6.55%		6.55%
Senior Notes [Member] \| Senior Notes Due 2048 [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 346.0		$ 345.9
Line of Credit [Member]
Debt Instrument [Line Items]
Amortization of Debt Issuance Costs	(1.6)	$ (1.6)
Line of Credit [Member] \| Line of Credit [Member] \| Syndicated Loan Facility [Member]
Debt Instrument [Line Items]
Long-term Debt	26.9		25.1
Line of Credit [Member] \| Line of Credit [Member] \| 3 Year Term Loan Agreement [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 72.0		$ 76.1