CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Statement [Abstract]
Revenues	$ 1,152,136	$ 1,226,920	$ 3,533,283	$ 3,593,395
Operating expenses:
Cost of revenues (exclusive of depreciation and amortization)	794,265	826,796	2,458,881	2,453,955
Selling, general and administrative expenses	194,829	198,021	601,093	667,825
Depreciation and amortization expense	23,092	21,876	68,642	69,126
Loss on sale of business	25,922	0	25,922	0
Income from operations	114,028	180,227	378,745	402,489
Interest and other income, net	13,931	4,228	37,162	5,642
Foreign exchange gain/(loss)	3,893	6,691	(6,725)	(102,035)
Income before provision for income taxes	131,852	191,146	409,182	306,096
Provision for income taxes	34,648	35,092	89,653	41,719
Net income	$ 97,204	$ 156,054	$ 319,529	$ 264,377
Net income per share:
Basic (in usd per share)	$ 1.68	$ 2.72	$ 5.52	$ 4.62
Diluted (in usd per share)	$ 1.65	$ 2.63	$ 5.40	$ 4.47
Shares used in calculation of net income per share:
Basic (in shares)	57,853	57,420	57,850	57,194
Diluted (in shares)	58,948	59,357	59,143	59,108