CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 323,398	$ 245,947	$ 143,348
Adjustments to reconcile net income to net cash provided by operating activities-
Amortization of identifiable intangible assets	43,404	47,795	40,505
Depreciation expense	38,162	33,552	28,439
Change in right-of-use assets	25,964	21,557	17,592
Bad debt expense	4,944	2,670	(1,452)
Deferred tax provision (benefit)	95,296	(94,505)	6,902
Amortization of debt financing costs	685	786	538
Gain on sale of assets	(2,302)	(1,585)	(1,540)
Changes in the fair value of contingent earn-out obligations	23,607	4,819	(7,820)
Stock-based compensation	12,939	10,532	10,593
(Increase) decrease in-
Receivables, net	(381,555)	(223,178)	(58,046)
Inventories	(29,688)	(13,495)	(5,651)
Prepaid expenses and other current assets	(11,137)	(26,238)	(8,623)
Costs and estimated earnings in excess of billings and unbilled accounts receivable	7,350	(9,643)	(17,271)
Other noncurrent assets	(152)	(995)	(1,174)
Increase (decrease) in-
Accounts payable and accrued liabilities	136,467	93,110	(5,171)
Billings in excess of costs and estimated earnings and deferred revenue	349,166	226,019	53,795
Other long-term liabilities	3,020	(15,617)	(14,813)
Net cash provided by operating activities	639,568	301,531	180,151
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(94,838)	(48,359)	(22,330)
Proceeds from sales of property and equipment	5,951	2,858	3,101
Cash paid for acquisitions, net of cash acquired	(102,261)	(49,217)	(227,493)
Payments for investments	(1,860)	(2,460)
Net cash used in investing activities	(193,008)	(97,178)	(246,722)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from revolving credit facility	285,000	555,000	275,000
Payments on revolving credit facility	(500,000)	(560,000)	(125,000)
Payments on term loan		(120,000)	(15,000)
Payments on other debt	(12,033)	(12,256)	(15,696)
Payments on finance lease liabilities		(899)	(3,805)
Debt financing costs		(2,297)
Payments of dividends to stockholders	(30,379)	(20,077)	(17,384)
Share repurchase	(21,184)	(38,216)	(27,054)
Shares received in lieu of tax withholding	(4,725)	(3,247)	(2,363)
Proceeds from exercise of options	18	1,086	5,634
Deferred acquisition payments		(50)	(400)
Payments for contingent consideration arrangements	(15,321)	(4,959)	(3,481)
Net cash provided by (used in) financing activities	(298,624)	(205,915)	70,451
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	147,936	(1,562)	3,880
CASH AND CASH EQUIVALENTS, beginning of period	57,214	58,776	54,896
CASH AND CASH EQUIVALENTS, end of period	$ 205,150	$ 57,214	$ 58,776