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Long-Term Debt - Long-Term Debt (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Interest rate		1.00%
3.57% due 2020, floating interest rate at Libor + 1.099% [Member]
Debt Instrument [Line Items]
Long-term debt maturity date	2020
Interest rate	3.57%
Description of floating rate basis	Libor + 1.099%
Basis spread on floating rate	1.099%
3.69% due 2020, floating interest rate at Libor + 1.056% [Member]
Debt Instrument [Line Items]
Long-term debt maturity date	2020
Interest rate	3.69%
Description of floating rate basis	Libor + 1.056%
Basis spread on floating rate	1.056%
0.50% due 2020, floating interest rate at Euribor + 0.817% [Member]
Debt Instrument [Line Items]
Long-term debt maturity date	2020
Interest rate	0.50%
Description of floating rate basis	Euribor + 0.817%
Basis spread on floating rate	0.817%
3.30% due 2021, floating interest rate at Libor + 0.525% [Member]
Debt Instrument [Line Items]
Long-term debt maturity date	2021
Interest rate	3.30%
Description of floating rate basis	Libor + 0.525%
Basis spread on floating rate	0.525%
3.46% due 2021, floating interest rate at Libor + 0.572% [Member]
Debt Instrument [Line Items]
Long-term debt maturity date	2021
Interest rate	3.46%
Description of floating rate basis	Libor + 0.572%
Basis spread on floating rate	0.572%
0.32% due 2028, floating interest rate at Libor 0.589% [Member]
Debt Instrument [Line Items]
Long-term debt maturity date	2028
Interest rate	0.32%
Description of floating rate basis	Euribor + 0.589%
Basis spread on floating rate	0.589%
Zero-coupon, due 2022 (Tranche A) [Member] | Senior Unsecured Convertible Bonds [Member]
Debt Instrument [Line Items]
Long-term debt maturity date	2022
Interest rate	0.00%
0.25%, due 2024 (Tranche B) [Member]
Debt Instrument [Line Items]
Interest rate	0.25%
0.25%, due 2024 (Tranche B) [Member] | Senior Unsecured Convertible Bonds [Member]
Debt Instrument [Line Items]
Long-term debt maturity date	2024
Interest rate	0.25%
0.31% (weighted average), due 2018-2023, fixed interest rate [Member]
Debt Instrument [Line Items]
Interest rate	0.31%
0.31% (weighted average), due 2018-2023, fixed interest rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Long-term debt maturity date	2018
0.31% (weighted average), due 2018-2023, fixed interest rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Long-term debt maturity date	2023
0.41% (weighted average), due 2018, fixed interest rate [Member]
Debt Instrument [Line Items]
Long-term debt maturity date	2018
Interest rate	0.41%
0.87% (weighted average), due 2020, fixed interest rate [Member]
Debt Instrument [Line Items]
Long-term debt maturity date	2020
Interest rate	0.87%

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Debt Instrument Maturity Year

+ References

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- Definition

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

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- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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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