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	$ 165,919	$ 164,240	$ 161,458
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	154,079	159,072	135,624
Losses from sale of investments	1	45	0
Share-based compensation expense	108,338	102,985	104,726
Provision for losses and sales adjustments - accounts receivable	8,233	2,781	2,831
Amortization of operating lease right-of-use assets	16,688	12,969	10,216
Deferred income tax benefit	(73,704)	(87,192)	(13,271)
Other	475	0	0
Changes in operating assets and liabilities, exclusive of effects of acquired companies:
Accounts receivable	(39,878)	(51,410)	17,608
Income tax payable	(41,201)	61,940	10,258
Prepaid expenses and other current assets	(19,668)	910	(23,863)
Accounts payable	41,485	(17,537)	(44,947)
Operating lease liabilities	(11,533)	(12,396)	(6,952)
Accrued liabilities	13,069	(24,344)	(24,822)
Deferred revenue	58,513	59,460	44,874
Other long-term liabilities	(376)	9,932	(1,987)
Net cash provided by operating activities	380,440	381,455	371,753
Cash flows from investing activities:
Additions to property and equipment	(20,519)	(22,529)	(33,919)
Purchase of marketable security investments	(10,617)	(29,935)	(77,450)
Proceeds and maturities from marketable security investments	49,412	71,034	131,449
Investment in software development	(32,490)	(27,622)	(21,693)
Cost of acquisitions, net of cash acquired	(62,759)	(163,921)	(2,089,706)
Other	13	443	384
Net cash used by investing activities	(76,960)	(172,530)	(2,090,935)
Cash flows from financing activities:
Payment on term loans	(345,000)	(360,000)	(145,000)
Proceeds from term loans	0	0	900,000
Proceeds from issuance of convertible senior notes	0	0	600,000
Payment of debt issuance costs	0	0	(27,165)
Purchase of treasury shares	0	0	(12,977)
Proceeds from exercise of stock options, net of withheld shares for taxes upon equity award	16,960	(890)	96,714
Contributions from employee stock purchase plan	16,196	16,651	13,158
Net cash (used) provided by financing activities	(311,844)	(344,239)	1,424,730
Net decrease in cash and cash equivalents	(8,364)	(135,314)	(294,452)
Cash and cash equivalents at beginning of period	173,857	309,171	603,623
Cash and cash equivalents at end of period	165,493	173,857	309,171
Supplemental cash flow information:
Cash paid for interest	19,154	21,256	17,728
Cash paid for income taxes, net	142,820	38,490	2,212
Non-cash investing and financing activities:
Non-cash additions to property and equipment	3,123	169	233
Issuance of shares for acquisitions	5,675	18,169	0
Purchase consideration for conversion of unvested restricted stock awards	$ 0	$ 0	$ 1,872