Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 997,861	$ 615,615
Short-term investments	476,362	442,473
Receivables, net	1,175,139	1,168,712
Inventory	30,442	23,027
Prepaid expenses and other	375,376	401,160
Total current assets	3,055,180	2,650,987
Property and equipment, net	1,803,027	1,804,083
Right-of-use assets	102,871	104,536
Software development costs, net	1,028,513	1,009,349
Goodwill	912,043	914,520
Intangible assets, net	316,368	329,249
Long-term investments	492,704	510,220
Other assets	197,704	198,152
Total assets	7,908,410	7,521,096
Current liabilities:
Accounts payable	279,256	235,755
Current installments of long-term debt	225,000	0
Deferred revenue	407,736	393,293
Accrued payroll and tax withholdings	313,184	309,814
Other current liabilities	237,964	229,764
Total current liabilities	1,463,140	1,168,626
Long-term Debt	1,611,102	1,336,069
Deferred income taxes	372,037	376,035
Other liabilities	149,694	157,799
Total liabilities	3,595,973	3,038,529
Shareholders' Equity:
Common stock, $0.01 par value, 500,000,000 shares authorized, 374,048,596 shares issued at March 31, 2021 and 373,224,832 shares issued at December 31, 2020	3,740	3,732
Additional paid-in capital	2,368,227	2,288,806
Retained earnings	6,580,612	6,475,551
Treasury stock, 72,276,054 shares at March 31, 2021 and 67,371,686 shares at December 31, 2020	(4,514,718)	(4,164,718)
Accumulated other comprehensive loss, net	(125,424)	(120,804)
Total shareholders' equity	4,312,437	4,482,567
Total liabilities and shareholders' equity	$ 7,908,410	$ 7,521,096
Common stock, par value	$ 0.01
Common Stock, Shares Authorized	500,000,000
Common stock, shares issued	374,048,596	373,224,832
Treasury Stock, Shares	72,276,054	67,371,686