Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 185,926	$ 36,151
Accounts receivable (less allowance for losses of $5,427 in 2017 and $3,396 in 2016)	227,127	200,334
Short-term investments	43,159	20,273
Prepaid expenses	27,252	21,039
Income tax receivable	11,339	2,895
Other current assets	1,997	2,268
Total current assets	496,800	282,960
Accounts receivable, long-term	7,536	2,480
Property and equipment, net	152,315	124,268
Other assets:
Goodwill	657,987	650,237
Other intangibles, net	236,444	267,259
Non-current investments and other assets	38,510	30,741
Total assets	1,589,592	1,357,945
Current liabilities:
Accounts payable	8,174	7,295
Accrued liabilities	64,675	55,989
Deferred revenue	309,461	298,217
Total current liabilities	382,310	361,501
Revolving line of credit	0	10,000
Deferred revenue, long-term	1,274	2,140
Deferred income taxes	38,914	68,779
Commitments and contingencies
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 in 2017 and 2016	481	481
Additional paid-in capital	626,867	556,663
Accumulated other comprehensive loss, net of tax	(46)	(46)
Retained earnings	599,821	435,876
Treasury stock, at cost; 10,262,182 and 11,381,733 shares in 2017 and 2016, respectively	(60,029)	(77,449)
Total shareholders' equity	1,167,094	915,525
Liabilities and Shareholders' equity, Total	$ 1,589,592	$ 1,357,945