CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 205,635	$ 188,699
Short-term investments	28,037	51,598
Total cash, cash equivalents and short-term investments	233,672	240,297
Settlement and merchant reserve assets	186,267	166,031
Trade accounts receivable:
Billed, net of allowance of $4,250 and $3,628	244,317	226,623
Unbilled	35,802	37,785
Income taxes receivable	6,414	2,167
Other current assets	41,727	41,688
Total current assets	748,199	714,591
Non-current assets:
Property and equipment, net of depreciation of $111,244 and $105,073	73,580	81,759
Operating lease right-of-use assets	86,034	110,756
Goodwill	321,330	272,322
Customer contract costs, net of amortization of $32,410 and $39,893	46,618	47,238
Deferred income taxes	8,584	10,205
Other assets	15,840	20,664
Total non-current assets	638,950	617,409
Total assets	1,387,149	1,332,000
Current liabilities:
Current portion of long-term debt	237,500	14,063
Operating lease liabilities	23,270	22,651
Customer deposits	43,546	39,992
Trade accounts payable	35,397	29,834
Accrued employee compensation	91,115	86,289
Settlement and merchant reserve liabilities	185,276	165,064
Deferred revenue	53,748	52,357
Income taxes payable	398	6,627
Other current liabilities	24,852	19,383
Total current liabilities	695,102	436,260
Non-current liabilities:
Long-term debt, net of unamortized discounts of $3,406 and $5,346	137,219	337,154
Operating lease liabilities	70,068	95,926
Deferred revenue	19,599	17,275
Income taxes payable	4,058	2,436
Deferred income taxes	7,752	5,109
Other non-current liabilities	13,107	15,445
Total non-current liabilities	251,803	473,345
Total liabilities	946,905	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; 4,704 and 5,929 shares reserved for employee stock purchase plan and stock incentive plans; 32,495 and 32,713 shares outstanding	705	700
Additional paid-in capital	488,303	470,557
Treasury stock, at cost; 36,713 and 35,980 shares	(930,106)	(894,126)
Accumulated other comprehensive income (loss):
Unrealized gains on short-term investments, net of tax	(6)	13
Cumulative foreign currency translation adjustments	(38,347)	(31,151)
Accumulated earnings	916,060	876,402
Total CSG stockholders' equity	436,609	422,395
Noncontrolling interest	3,635
Total stockholders' equity	440,244	422,395
Total liabilities and stockholders' equity	1,387,149	1,332,000
Software
Non-current assets:
Intangible assets	29,757	26,453
Acquired customer contracts
Non-current assets:
Intangible assets	$ 57,207	$ 48,012