Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

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Period Type:	instant

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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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.

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- Definition

Face (par) amount of the original debt instrument that was repurchased.

+ References

No definition available.

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Company's Debt Maturities on Calendar Year Basis (Parenthetical) (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Aug. 02, 2017	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Jul. 31, 2016	Jun. 30, 2016	Mar. 18, 2013	May 23, 2011
Debt Instrument [Line Items]
Principal amount of long term debt			$ 0.0
Convertible Notes \| 1.50% Senior Subordinated Notes Due March 15, 2018
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	1.50%			1.50%	1.50%			1.50%	2.50%
Debt instrument, par value of notes repurchased	$ 58.9			$ 104.9		$ 53.2	$ 51.7
Principal amount of long term debt	236.2							$ 400.0	$ 300.0
Convertible Notes \| FY 2016 and Current Quarter \| 1.50% Senior Subordinated Notes Due March 15, 2018
Debt Instrument [Line Items]
Debt instrument, par value of notes repurchased	163.8
Variable Funding Notes
Debt Instrument [Line Items]
Principal amount of long term debt	100.0
2017 Senior Secured Term Loan
Debt Instrument [Line Items]
Principal amount of long term debt	$ 298.5	$ 300.0