CONDENSED CONSOLIDATED BALANCE SHEETS - UNAUDITED - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 150,609	$ 188,699
Short-term investments	54,539	51,598
Total cash, cash equivalents and short-term investments	205,148	240,297
Settlement assets	108,578	149,785
Trade accounts receivable:
Billed, net of allowance of $3,718 and $3,628	247,025	226,623
Unbilled	40,789	37,785
Income taxes receivable	2,421	2,167
Other current assets	39,047	41,688
Total current assets	643,008	698,345
Non-current assets:
Property and equipment, net of depreciation of $110,797 and $105,073	81,944	81,759
Operating lease right-of-use assets	106,173	110,756
Intangible assets	71,858	74,465
Goodwill	273,265	272,322
Customer costs, net of amortization of $42,802 and $39,893	47,334	47,238
Deferred income taxes	9,892	10,205
Other assets	41,007	36,910
Total non-current assets	631,473	633,655
Total assets	1,274,481	1,332,000
Current liabilities:
Current portion of long-term debt, net of unamortized discounts of $3,119 and zero	241,881	14,063
Operating lease liabilities	23,309	22,651
Customer deposits	32,565	39,992
Trade accounts payable	32,949	29,834
Accrued employee compensation	71,120	86,289
Settlement liabilities	107,023	148,819
Deferred revenue	55,840	52,357
Income taxes payable	5,797	6,627
Other current liabilities	17,249	19,383
Total current liabilities	587,733	420,015
Non-current liabilities:
Long-term debt, net of unamortized discounts of $1,017 and $5,346	107,733	337,154
Operating lease liabilities	91,028	95,926
Deferred revenue	15,505	17,275
Income taxes payable	2,467	2,436
Deferred income taxes	11,569	5,109
Other non-current liabilities	30,731	31,690
Total non-current liabilities	259,033	489,590
Total liabilities	846,766	909,605
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; 32,963 and 32,713 shares outstanding	704	700
Additional paid-in capital	471,364	470,557
Treasury stock, at cost; 36,122 and 35,980 shares	(900,644)	(894,126)
Accumulated other comprehensive income (loss):
Unrealized gains on short-term investments, net of tax	7	13
Cumulative foreign currency translation adjustments	(31,506)	(31,151)
Accumulated earnings	887,790	876,402
Total stockholders' equity	427,715	422,395
Total liabilities and stockholders' equity	1,274,481	1,332,000
Software
Non-current assets:
Intangible assets	25,585	26,453
Acquired customer contracts
Non-current assets:
Intangible assets	$ 46,273	$ 48,012