CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 607,391	$ 777,139
Short-term investments	237	225
Accounts receivable, less allowance for doubtful accounts of $8,600 and $8,000, respectively	268,526	317,700
Other receivables and current assets	186,657	216,113
Total current assets	1,062,811	1,311,177
Long-term assets:
Property and equipment, net	63,301	61,655
Operating lease right-of-use assets	99,991	0
Goodwill	1,748,228	1,572,455
Other intangible assets, net	278,327	211,272
Other long-term assets	97,699	82,775
Deferred income taxes	21,906	26,630
Total long-term assets	2,309,452	1,954,787
Total assets	3,372,263	3,265,964
Current liabilities:
Accounts payable	11,502	7,953
Accrued bonuses and commissions	20,506	79,945
Accrued income taxes	15,694	8,726
Other accrued expenses and liabilities	124,818	99,559
Deferred revenue	330,890	328,584
Total current liabilities	503,410	524,767
Long-term liabilities:
Deferred income taxes	38,370	30,077
Long-term operating lease liabilities	87,259	0
Other long-term liabilities	58,843	61,573
Total long-term liabilities	184,472	91,650
Commitments and contingencies
Stockholders' equity:
Preferred stock, $.01 par value; 2,000,000 shares authorized; zero shares issued or outstanding	0	0
Common stock, $.01 par value; 300,000,000 shares authorized; 93,236,023 shares issued	932	932
Additional paid-in capital	824,997	867,462
Retained earnings	3,005,641	2,919,411
Treasury stock, at cost: 9,357,968 and 9,601,670 shares, respectively	(1,077,252)	(1,075,879)
Accumulated other comprehensive loss	(69,937)	(62,379)
Total stockholders' equity	2,684,381	2,649,547
Total liabilities and stockholders' equity	$ 3,372,263	$ 3,265,964