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

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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+ 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)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
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Schedule of Debt Obligations (Parenthetical) (Detail) - Convertible Notes - USD ($) $ in Millions			6 Months Ended
	Jun. 01, 2016	Mar. 18, 2013	Jun. 30, 2016	Apr. 30, 2016	Apr. 04, 2016	Dec. 31, 2015	Jun. 30, 2015	May 23, 2011
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%
Debt instrument, par value of notes repurchased			$ 51.7
Debt instrument, maturity date		Mar. 15, 2018
2.50% Senior Subordinated Notes Due June 2016
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage			2.50%		2.50%	2.50%	2.50%	2.50%
Debt instrument, par value of notes repurchased				$ 143.9
Repayment of remaining outstanding balance of convertible notes upon maturity	$ 156.1
Debt instrument, maturity date			Jun. 01, 2016