Debt - Schedule of Senior Notes (Detail) € in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2015 EUR (€)	Dec. 31, 2014 EUR (€)
Line Of Credit Facility Covenant Compliance [Line Items]
Principal Amount	$ 11,621,000
May 2015 [Member]
Line Of Credit Facility Covenant Compliance [Line Items]
Principal Amount	$ 785,470		€ 700,000
Stated Interest Rate	1.40%		1.40%
Effective Interest Rate	1.50%		1.50%
Maturity Date	2021-05
October 2015 [Member]
Line Of Credit Facility Covenant Compliance [Line Items]
Principal Amount	$ 750,000
Stated Interest Rate	3.80%		3.80%
Effective Interest Rate	4.00%		4.00%
Maturity Date	2025-11
February 2014 [Member]
Line Of Credit Facility Covenant Compliance [Line Items]
Principal Amount		$ 959,420		€ 700,000
Stated Interest Rate		3.40%		3.40%
Effective Interest Rate		3.50%		3.50%
Maturity Date		2024-02
June 2014 [Member]
Line Of Credit Facility Covenant Compliance [Line Items]
Principal Amount		$ 680,550		€ 500,000
Stated Interest Rate		3.00%		3.00%
Effective Interest Rate		3.10%		3.10%
Maturity Date		2026-06
October 2014 [Member]
Line Of Credit Facility Covenant Compliance [Line Items]
Principal Amount		$ 756,420		€ 600,000
Stated Interest Rate		1.40%		1.40%
Effective Interest Rate		1.40%		1.40%
Maturity Date		2020-10