CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 518,685	$ 232,682
Accounts receivable (less allowance for losses and sales adjustments of $9,760 in 2020 and $4,302 in 2019)	362,667	374,089
Short-term investments	55,595	39,399
Prepaid expenses	29,743	24,717
Income tax receivable	20,752	6,482
Other current assets	3,157	2,328
Total current assets	990,599	679,697
Accounts receivable, long-term	24,459	22,432
Operating lease right-of-use assets	15,321	18,992
Property and equipment, net	170,833	171,861
Other assets:
Goodwill	840,028	840,117
Other intangibles, net	341,999	378,914
Non-current investments	75,278	42,235
Other non-current assets	33,646	37,366
Total assets	2,492,163	2,191,614
Current liabilities:
Accounts payable	11,073	14,977
Accrued liabilities	81,688	75,234
Operating lease liabilities	5,780	6,387
Current income tax payable	0	0
Deferred revenue	436,504	412,495
Total current liabilities	535,045	509,093
Revolving line of credit	0	0
Deferred revenue, long-term	118	199
Deferred income taxes	45,985	48,442
Operating lease liabilities, long-term	12,870	16,822
Commitments and contingencies	0	0
Shareholders' equity:
Preferred stock, $10.00 par value; 1,000,000 shares authorized; none issued	0	0
Common stock, $0.01 par value; 100,000,000 shares authorized; 48,147,969 shares issued and outstanding as of September 30, 2020 and December 31, 2019	481	481
Additional paid-in capital	872,963	739,478
Accumulated other comprehensive loss, net of tax	(46)	(46)
Retained earnings	1,058,062	917,336
Treasury stock, at cost; 7,832,824 and 8,839,352 shares in 2020 and 2019, respectively	(33,315)	(40,191)
Total shareholders' equity	1,898,145	1,617,058
Total liabilities and shareholders' equity	$ 2,492,163	$ 2,191,614