CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 41,327	$ 33,087
Accounts receivable (less allowance for losses of $1,560 in 2016 and $1,640 in 2015)	209,483	176,360
Short-term investments	22,642	13,423
Prepaid expenses	22,976	22,334
Income tax receivable	23,994	21,080
Other current assets	3,529	1,931
Total current assets	323,951	268,215
Accounts receivable, long-term	2,579	2,777
Property and equipment, net	115,886	101,112
Other assets:
Goodwill	655,393	653,666
Other intangibles, net	285,491	295,378
Non-current investments and other assets	29,752	35,422
Total assets	1,413,052	1,356,570
Current liabilities:
Accounts payable	6,574	6,789
Accrued liabilities	49,875	49,156
Deferred revenue	296,481	281,627
Total current liabilities	352,930	337,572
Revolving line of credit	135,000	66,000
Deferred revenue, long-term	3,704	3,115
Deferred income taxes	92,110	91,026
Commitments and contingencies
Shareholders' equity:
Preferred stock, $10.00 par value; 1,000,000 shares authorized; none issued
Common stock, $0.01 par value; 100,000,000 shares authorized; 48,147,969 shares issued and outstanding as of June 30, 2016 and December 31, 2015	481	481
Additional paid-in capital	605,179	607,755
Accumulated other comprehensive loss, net of tax	(46)	(46)
Retained earnings	361,970	326,019
Treasury stock, at cost; 11,867,051 and 11,373,666 shares in 2016 and 2015, respectively	(138,276)	(75,352)
Total shareholders' equity	829,308	858,857
Liabilities and Shareholders' equity, Total	$ 1,413,052	$ 1,356,570

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.