Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities
Net income	$ 5,698	$ 7,717	$ 11,908
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	82,410	92,735	85,693
Provision for credit losses and sales returns	11,450	13,230	8,725
Stock-based compensation expense	120,379	87,257	58,633
Deferred taxes	(2,429)	8,837	(3,600)
Amortization of deferred financing costs and discount	1,570	781	752
Other non-cash adjustments	10,490	2,958	4,906
Changes in operating assets and liabilities, net of acquisition and disposal of businesses:
Accounts receivable	(6,525)	(18,414)	(6,569)
Prepaid expenses and other assets	(2,048)	22,568	6,383
Trade accounts payable	(9,670)	(19,997)	12,900
Accrued expenses and other liabilities	(8,190)	(49,232)	(9,718)
Deferred revenue	10,526	(485)	12,464
Net cash provided by operating activities	213,661	147,955	182,477
Cash flows from investing activities
Purchase of property and equipment	(11,664)	(29,690)	(11,492)
Capitalized software development costs	(40,489)	(42,157)	(46,874)
Purchase of net assets of acquired companies, net of cash and restricted cash acquired	(419,120)	0	(109,353)
Other investing activities	0	0	500
Net cash used in investing activities	(471,273)	(71,847)	(167,219)
Cash flows from financing activities
Proceeds from issuance of debt	582,200	748,500	424,000
Payments on debt	(152,971)	(747,563)	(344,500)
Debt issuance costs	(3,106)	(4,586)	0
Employee taxes paid for withheld shares upon equity award settlement	(39,404)	(21,425)	(23,781)
Proceeds from exercise of stock options	0	4	7
Change in due to customers	(13,464)	61,214	77,793
Change in customer funds receivable	(731)	138	1,301
Purchase of treasury stock	(108,416)	(41,001)	0
Dividend payments to stockholders	0	(5,960)	(23,607)
Net cash provided by (used in) financing activities	264,108	(10,679)	111,213
Effect of exchange rate on cash, cash equivalents and restricted cash	297	2,245	978
Net increase in cash, cash equivalents and restricted cash	6,793	67,674	127,449
Cash, cash equivalents and restricted cash, beginning of year	644,969	577,295	449,846
Cash, cash equivalents and restricted cash, end of year	651,762	644,969	577,295
Cash (paid) received during the year for:
Interest	(16,386)	(15,716)	(19,926)
Taxes, net of refunds	(10,073)	(3,563)	(383)
Non-cash investing and financing activities:
Purchase of property and equipment by assuming directly related liabilities	0	(61,064)	0
Purchase of equipment and other assets included in accounts payable	(1,747)	(840)	(794)
Acquired restricted cash liabilities due to customers	0	0	46,838
Stock Issued	(303,633)	0	$ 0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	55,146	35,750
Total restricted cash	596,616	609,219
Total cash, cash equivalents and restricted cash in the statement of cash flows	$ 651,762	$ 644,969