CONDENSED CONSOLIDATED BALANCE SHEETS - UNAUDITED - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 123,572	$ 139,277
Short-term investments	18,333	23,603
Total cash, cash equivalents and short-term investments	141,905	162,880
Settlement assets	87,853	124,627
Trade accounts receivable:
Billed, net of allowance of $2,897 and $3,115	244,936	235,827
Unbilled	40,432	37,227
Income taxes receivable	3,161	6,720
Other current assets	32,441	32,286
Total current assets	550,728	599,567
Non-current assets:
Property and equipment, net of depreciation of $98,122 and $93,278	85,895	81,813
Operating lease right-of-use assets	78,263
Intangible assets	98,188	101,856
Goodwill	258,512	255,816
Client contract costs, net of amortization of $49,100 and $43,051	37,420	37,289
Deferred income taxes	10,821	11,087
Other assets	27,220	26,934
Total non-current assets	596,319	514,795
Total assets	1,147,047	1,114,362
Current liabilities:
Current portion of long-term debt	7,500	7,500
Operating lease liabilities	18,737
Client deposits	34,501	36,889
Trade accounts payable	40,792	45,386
Accrued employee compensation	51,474	61,107
Settlement liabilities	86,471	123,613
Deferred revenue	47,212	40,236
Income taxes payable	625	218
Other current liabilities	32,168	35,442
Total current liabilities	319,480	350,391
Non-current liabilities:
Long-term debt, net of unamortized discounts of $13,444 and $14,549	351,556	352,326
Operating lease liabilities	66,842
Deferred revenue	16,928	17,527
Income taxes payable	2,638	2,284
Deferred income taxes	8,798	8,205
Other non-current liabilities	13,295	22,605
Total non-current liabilities	460,057	402,947
Total liabilities	779,537	753,338
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; 33,280 and 33,158 shares outstanding	697	693
Common stock warrants; 439 warrants vested; 1,425 issued	9,082	9,082
Additional paid-in capital	441,484	441,417
Treasury stock, at cost; 35,028 and 34,779 shares	(851,650)	(842,360)
Accumulated other comprehensive income (loss):
Unrealized gain on short-term investments, net of tax	20	2
Cumulative foreign currency translation adjustments	(39,090)	(42,937)
Accumulated earnings	806,967	795,127
Total stockholders' equity	367,510	361,024
Total liabilities and stockholders' equity	1,147,047	1,114,362
Software
Non-current assets:
Intangible assets	35,274	36,400
Acquired client contracts
Non-current assets:
Intangible assets	$ 62,914	$ 65,456