CONDENSED CONSOLIDATED BALANCE SHEETS - UNAUDITED - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 113,777	$ 139,277
Short-term investments	17,674	23,603
Total cash, cash equivalents and short-term investments	131,451	162,880
Settlement assets	88,575	124,627
Trade accounts receivable:
Billed, net of allowance of $2,861 and $3,115	265,795	235,827
Unbilled	39,275	37,227
Income taxes receivable	7,206	6,720
Other current assets	40,326	32,286
Total current assets	572,628	599,567
Non-current assets:
Property and equipment, net of depreciation of $102,018 and $93,278	84,354	81,813
Operating lease right-of-use assets	94,028
Intangible assets	93,552	101,856
Goodwill	256,890	255,816
Client contract costs, net of amortization of $30,169 and $43,051	39,724	37,289
Deferred income taxes	10,442	11,087
Other assets	28,099	26,934
Total non-current assets	607,089	514,795
Total assets	1,179,717	1,114,362
Current liabilities:
Current portion of long-term debt	8,438	7,500
Operating lease liabilities	22,279
Client deposits	36,369	36,889
Trade accounts payable	44,874	45,386
Accrued employee compensation	51,434	61,107
Settlement liabilities	87,194	123,613
Deferred revenue	48,277	40,236
Income taxes payable	430	218
Other current liabilities	36,289	35,442
Total current liabilities	335,584	350,391
Non-current liabilities:
Long-term debt, net of unamortized discounts of $12,327 and $14,549	349,860	352,326
Operating lease liabilities	77,993
Deferred revenue	15,463	17,527
Income taxes payable	2,684	2,284
Deferred income taxes	11,204	8,205
Other non-current liabilities	12,605	22,605
Total non-current liabilities	469,809	402,947
Total liabilities	805,393	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; 33,062 and 33,158 shares outstanding	696	693
Common stock warrants; 439 warrants vested; 1,425 issued	9,082	9,082
Additional paid-in capital	446,512	441,417
Treasury stock, at cost; 35,172 and 34,779 shares	(858,186)	(842,360)
Accumulated other comprehensive income (loss):
Unrealized gain on short-term investments, net of tax	30	2
Cumulative foreign currency translation adjustments	(42,908)	(42,937)
Accumulated earnings	819,098	795,127
Total stockholders' equity	374,324	361,024
Total liabilities and stockholders' equity	1,179,717	1,114,362
Software
Non-current assets:
Intangible assets	33,322	36,400
Acquired client contracts
Non-current assets:
Intangible assets	$ 60,230	$ 65,456