CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Statement [Abstract]
Revenues	$ 1,167,527	$ 1,152,136	$ 3,479,589	$ 3,533,283
Operating expenses:
Cost of revenues (exclusive of depreciation and amortization)	763,992	794,265	2,409,183	2,458,881
Selling, general and administrative expenses	206,820	194,829	599,331	601,093
Depreciation and amortization expense	19,736	23,092	63,003	68,642
Loss on sale of business	0	25,922	0	25,922
Income from operations	176,979	114,028	408,072	378,745
Interest and other income, net	13,347	13,931	40,425	37,162
Foreign exchange (loss)/gain	(710)	3,893	(1,416)	(6,725)
Income before provision for income taxes	189,616	131,852	447,081	409,182
Provision for income taxes	53,270	34,648	95,847	89,653
Net income	$ 136,346	$ 97,204	$ 351,234	$ 319,529
Net income per share:
Basic (in usd per share)	$ 2.40	$ 1.68	$ 6.11	$ 5.52
Diluted (in usd per share)	$ 2.37	$ 1.65	$ 6.04	$ 5.40
Shares used in calculation of net income per share:
Basic (in shares)	56,910	57,853	57,445	57,850
Diluted (in shares)	57,425	58,948	58,166	59,143