Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 428,569	$ 752,895
Short-term investments, available-for-sale	21,096	124,113
Accounts receivable, net of allowances of $22,788 and $25,868 at September 30, 2021 and December 31, 2020, respectively	532,002	858,009
Inventories, net	24,442	20,089
Prepaid expenses and other current assets	333,675	236,000
Total current assets	1,339,784	1,991,106
Long-term investments, available-for-sale	14,328	14,365
Property and equipment, net	229,760	208,811
Operating lease right-of-use assets, net	191,856	187,129
Goodwill	3,455,772	1,798,408
Other intangible assets, net	816,909	81,491
Deferred tax assets, net	230,662	386,504
Other assets	257,173	222,533
Total assets	6,536,244	4,890,347
Current liabilities:
Accounts payable	127,161	92,266
Accrued expenses and other current liabilities	367,630	507,185
Income taxes payable	57,783	42,760
Current portion of deferred revenues	1,464,176	1,510,216
Total current liabilities	2,016,750	2,152,427
Long-term portion of deferred revenues	314,272	392,360
Long-term debt	3,325,119	1,732,622
Long-term income taxes payable	204,782	232,086
Operating lease liabilities	184,490	195,767
Other liabilities	91,092	72,942
Commitments and contingencies
Stockholders' equity:
Preferred stock at $.01 par value: 5,000 shares authorized, none issued and outstanding	0	0
Common stock at $.001 par value: 1,000,000 shares authorized; 324,825 and 321,964 shares issued and outstanding at September 30, 2021 and December 31, 2020, respectively	325	322
Additional paid-in capital	6,942,847	6,608,018
Retained earnings	5,045,453	4,984,333
Accumulated other comprehensive loss	(6,862)	(3,649)
Stockholders' equity before treasury stock	11,981,763	11,589,024
Less - common stock in treasury, at cost (200,204 and 199,443 shares at September 30, 2021 and December 31, 2020, respectively)	(11,582,024)	(11,476,881)
Total stockholders' equity	399,739	112,143
Total liabilities and stockholders' equity	$ 6,536,244	$ 4,890,347