Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities:
Net income	$ 584,201	$ 147,138
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	160,749	162,603
Stock-based compensation expense	81,702	56,308
Deferred taxes	449	(6,548)
Loss on extinguishment of debt	0	44,814
Reduction in the carrying amount of operating lease right-of-use assets	56,162	62,876
Amortization and write-off of deferred financing fees	3,036	7,487
Amortization of deferred swap losses from de-designation	0	10,320
(Gain) loss on de-designated swaps	(12,149)	476
Changes in assets and liabilities:
Fees receivable, net	257,541	369,119
Deferred commissions	6,783	56,094
Prepaid expenses and other current assets	(18,418)	(9,104)
Other assets	(23,979)	(3,509)
Deferred revenues	103,565	(210,170)
Accounts payable and accrued and other liabilities	(121,958)	(45,074)
Cash provided by operating activities	1,077,684	642,830
Investing activities:
Additions to property, equipment and leasehold improvements	(38,670)	(60,845)
Acquisitions - cash paid (net of cash acquired)	(23,030)	0
Cash used in investing activities	(61,700)	(60,845)
Financing activities:
Proceeds from employee stock purchase plan	13,527	13,813
Proceeds from borrowings	600,000	2,000,000
Early redemption premium payment	0	(30,752)
Payments of deferred financing fees	(7,320)	(23,627)
Proceeds from revolving credit facility	0	327,000
Payments on revolving credit facility	(5,000)	(475,000)
Payments on borrowings	(106,585)	(2,053,342)
Purchases of treasury stock	(1,438,808)	(76,117)
Cash used in financing activities	(944,186)	(318,025)
Net increase in cash and cash equivalents and restricted cash	71,798	263,960
Effects of exchange rates on cash and cash equivalents	(14,651)	8,919
Cash and cash equivalents, beginning of period	712,583	280,836
Cash and cash equivalents and restricted cash, end of period	$ 769,730	$ 553,715