SEGMENT INFORMATION - Operating Revenues by Geographic Area (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues	$ 621,157	$ 551,806	$ 1,213,375	$ 1,111,751
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues	256,434	229,732	494,850	463,088
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues	27,574	23,642	55,110	46,109
Total Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues	284,008	253,374	549,960	509,197
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues	99,692	89,187	191,352	176,173
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues	139,851	122,515	278,170	254,088
Total EMEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues	239,543	211,702	469,522	430,261
Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues	24,285	22,843	50,302	46,033
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues	73,321	63,887	143,591	126,260
Total Asia & Australia
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating revenues	$ 97,606	$ 86,730	$ 193,893	$ 172,293