Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 246,404	$ 615,615
Short-term investments	638,488	442,473
Receivables, net	1,237,230	1,168,712
Inventory	20,168	23,027
Prepaid expenses and other	398,510	401,160
Total current assets	2,540,800	2,650,987
Property and equipment, net	1,768,617	1,804,083
Right-of-use assets	95,666	104,536
Software development costs, net	1,001,440	1,009,349
Goodwill	1,129,699	914,520
Intangible assets, net	492,547	329,249
Long-term investments	497,350	510,220
Other assets	194,983	198,152
Total assets	7,721,102	7,521,096
Current liabilities:
Accounts payable	332,959	235,755
Current installments of long-term debt	225,000	0
Deferred revenue	429,219	393,293
Accrued payroll and tax withholdings	332,513	309,814
Other current liabilities	223,203	229,764
Total current liabilities	1,542,894	1,168,626
Long-term Debt	1,611,154	1,336,069
Deferred income taxes	389,018	376,035
Other liabilities	151,552	157,799
Total liabilities	3,694,618	3,038,529
Shareholders' Equity:
Common stock, $0.01 par value, 500,000,000 shares authorized, 376,935,912 shares issued at June 30, 2021 and 373,224,832 shares issued at December 31, 2020	3,769	3,732
Additional paid-in capital	2,509,545	2,288,806
Retained earnings	6,546,615	6,475,551
Treasury stock, 77,455,570 shares at June 30, 2021 and 67,371,686 shares at December 31, 2020	(4,914,718)	(4,164,718)
Accumulated other comprehensive loss, net	(118,727)	(120,804)
Total shareholders' equity	4,026,484	4,482,567
Total liabilities and shareholders' equity	$ 7,721,102	$ 7,521,096
Common stock, par value	$ 0.01
Common Stock, Shares Authorized	500,000,000
Common stock, shares issued	376,935,912	373,224,832
Treasury Stock, Shares	77,455,570	67,371,686