Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 459,540	$ 615,615
Short-term investments	322,634	442,473
Receivables, net	1,219,849	1,168,712
Inventory	25,389	23,027
Prepaid expenses and other	412,744	401,160
Total current assets	2,440,156	2,650,987
Property and equipment, net	1,717,630	1,804,083
Right-of-use assets	89,619	104,536
Software development costs, net	1,008,440	1,009,349
Goodwill	1,126,843	914,520
Intangible assets, net	476,067	329,249
Long-term investments	488,454	510,220
Other assets	195,951	198,152
Total assets	7,543,160	7,521,096
Current liabilities:
Accounts payable	311,196	235,755
Current installments of long-term debt	225,000	0
Deferred revenue	438,063	393,293
Accrued payroll and tax withholdings	344,879	309,814
Other current liabilities	232,187	229,764
Total current liabilities	1,551,325	1,168,626
Long-term Debt	1,611,205	1,336,069
Deferred income taxes	389,843	376,035
Other liabilities	150,884	157,799
Total liabilities	3,703,257	3,038,529
Shareholders' Equity:
Common stock, $0.01 par value, 500,000,000 shares authorized, 378,558,251 shares issued at September 30, 2021 and 373,224,832 shares issued at December 31, 2020	3,785	3,732
Additional paid-in capital	2,598,853	2,288,806
Retained earnings	6,656,679	6,475,551
Treasury stock, 82,216,073 shares at September 30, 2021 and 67,371,686 shares at December 31, 2020	(5,289,718)	(4,164,718)
Accumulated other comprehensive loss, net	(129,696)	(120,804)
Total shareholders' equity	3,839,903	4,482,567
Total liabilities and shareholders' equity	$ 7,543,160	$ 7,521,096
Common stock, par value	$ 0.01
Common Stock, Shares Authorized	500,000,000
Common stock, shares issued	378,558,251	373,224,832
Treasury Stock, Shares	82,216,073	67,371,686