CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 188,699	$ 156,548
Short-term investments	51,598	26,109
Total cash, cash equivalents and short-term investments	240,297	182,657
Settlement assets	149,785	169,327
Trade accounts receivable:
Billed, net of allowance of $3,628 and $3,735	226,623	244,058
Unbilled	37,785	33,450
Income taxes receivable	2,167	4,297
Other current assets	41,688	35,293
Total current assets	698,345	669,082
Non-current assets:
Property and equipment, net of depreciation of $105,073 and $98,029	81,759	84,429
Operating lease right-of-use assets	110,756	94,847
Intangible assets	26,453	32,526
Goodwill	272,322	259,164
Customer contract costs, net of amortization of $39,893 and $31,526	47,238	50,746
Deferred income taxes	10,205	9,392
Other assets	36,910	27,739
Total non-current assets	633,655	613,948
Total assets	1,332,000	1,283,030
Current liabilities:
Current portion of long-term debt	14,063	10,313
Operating lease liabilities	22,651	22,442
Customer deposits	39,992	38,687
Trade accounts payable	29,834	32,704
Accrued employee compensation	86,289	77,527
Settlement liabilities	148,819	168,342
Deferred revenue	52,357	45,094
Income taxes payable	6,627	2,806
Other current liabilities	19,383	20,778
Total current liabilities	420,015	418,693
Non-current liabilities:
Long-term debt, net of unamortized discounts of $5,346 and $10,053	337,154	346,509
Operating lease liabilities	95,926	78,936
Deferred revenue	17,275	18,552
Income taxes payable	2,436	2,543
Deferred income taxes	5,109	6,376
Other non-current liabilities	31,690	14,759
Total non-current liabilities	489,590	467,675
Total liabilities	909,605	886,368
Stockholders' equity:
Preferred stock, par value $.01 per share; 10,000 shares authorized; zero shares issued and outstanding
Common stock, par value $.01 per share; 100,000 shares authorized; 5,929 and 3,661 shares reserved for employee stock purchase plan and stock incentive plans; 32,713 and 32,891 shares outstanding	700	696
Additional paid-in capital	470,557	454,663
Treasury stock, at cost; 35,980 and 35,356 shares	(894,126)	(867,817)
Accumulated other comprehensive income (loss):
Unrealized gains on short-term investments, net of tax	13	16
Cumulative foreign currency translation adjustments	(31,151)	(39,519)
Accumulated earnings	876,402	848,623
Total stockholders' equity	422,395	396,662
Total liabilities and stockholders' equity	1,332,000	1,283,030
Software
Non-current assets:
Intangible assets	26,453	32,526
Acquired customer contracts
Non-current assets:
Intangible assets	$ 48,012	$ 55,105