Segment Information - Operating Lease Right-of-Use Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating lease right-of-use assets	$ 1,475,057	$ 1,475,367	$ 1,468,762
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating lease right-of-use assets	363,515	387,598
Americas | U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating lease right-of-use assets	334,700	373,700
EMEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating lease right-of-use assets	547,547	521,129
Asia-Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating lease right-of-use assets	$ 563,995	$ 566,640