CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Statement [Abstract]
Revenues	$ 1,146,597	$ 1,170,206	$ 2,312,062	$ 2,381,147
Operating expenses:
Cost of revenues (exclusive of depreciation and amortization)	810,857	808,715	1,645,191	1,664,616
Selling, general and administrative expenses	194,058	194,377	392,511	406,264
Depreciation and amortization expense	21,121	22,768	43,267	45,550
Income from operations	120,561	144,346	231,093	264,717
Interest and other income, net	12,036	11,710	27,078	23,231
Foreign exchange gain/(loss)	1,213	(6,010)	(706)	(10,618)
Income before provision for income taxes	133,810	150,046	257,465	277,330
Provision for income taxes	35,165	30,013	42,577	55,005
Net income	$ 98,645	$ 120,033	$ 214,888	$ 222,325
Net income per share:
Basic (in usd per share)	$ 1.71	$ 2.07	$ 3.72	$ 3.84
Diluted (in usd per share)	$ 1.70	$ 2.03	$ 3.67	$ 3.75
Shares used in calculation of net income per share:
Basic (in shares)	57,594	57,993	57,716	57,848
Diluted (in shares)	58,149	59,181	58,540	59,240