Segment Information - Long-Lived Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Company's long-lived assets	$ 9,696,692	$ 9,394,602
Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Company's long-lived assets	4,470,166	4,425,077
EMEA [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Company's long-lived assets	3,448,277	3,265,088
Asia-Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Company's long-lived assets	$ 1,778,249	$ 1,704,437