Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net income	$ 105,354	$ 70,887	$ 78,299
Adjustments to reconcile net income to net cash provided by operating activities:
(Gain) loss on sale of operations, net of tax	(413)	(5,995)	509
Depreciation and amortization expense	32,895	27,078	23,139
Bad debt expense, net of recoveries	1,173	3,054	4,409
Adjustment to contingent earnout liability, net	2,435	2,367	(629)
Deferred income taxes	13,877	9,234	(770)
Stock-based compensation expense	14,689	11,407	8,869
Other, net	(1,817)	(126)	485
Changes in assets and liabilities, net of acquisitions and divestitures:
Accounts receivable, net	(61,106)	(17,040)	6,714
Other assets	(11,855)	3,474	1,472
Accounts payable	14,363	3,312	(8,800)
Income taxes payable	(5,578)	(4,108)	(236)
Accrued personnel costs	24,009	24,525	19,788
Other liabilities	(1,876)	3,109	13,667
Net cash provided by continuing operations	126,150	131,178	146,916
Operating cash flows used in discontinued operations	(18)	(24)	(71)
Net cash provided by operating activities	126,132	131,154	146,845
Cash flows from investing activities:
Business acquisitions and purchases of client lists, net of cash acquired	(79,141)	(66,734)	(71,430)
Purchases of client fund investments	(19,771)	(26,980)	(3,447)
Proceeds from the sales and maturities of client fund investments	12,400	14,877	37,487
Proceeds from sales of assets and divested operations	3,022	9,710	711
Additions to property and equipment	(8,641)	(8,984)	(11,576)
Other, net	(6,987)	(3,899)	1,849
Net cash used in investing activities	(99,118)	(82,010)	(46,406)
Cash flows from financing activities:
Proceeds from bank debt	824,900	852,100	592,354
Payment of bank debt	(714,500)	(804,800)	(589,854)
Payment for acquisition of treasury stock	(122,538)	(97,450)	(56,496)
Indirect repurchase of shares for minimum tax withholding	(7,289)	(3,037)	(2,040)
Changes in client funds obligations	15,352	(8,874)	(13,747)
Payment of contingent consideration of acquisitions	(21,231)	(14,084)	(12,859)
Proceeds from exercise of stock options	10,035	7,311	6,486
Other, net	(2,072)	(171)	(453)
Net cash used in financing activities	(17,343)	(69,005)	(76,609)
Net increase (decrease) in cash, cash equivalents and restricted cash	9,671	(19,861)	23,830
Cash, cash equivalents and restricted cash at beginning of year	150,474	170,335	146,505
Cash, cash equivalents and restricted cash at end of year	160,145	150,474	170,335
Reconciliation of cash, cash equivalents and restricted cash to the Consolidated Balance Sheets
Cash and cash equivalents	4,697	1,997	4,652
Restricted cash	28,487	30,383	23,951
Cash equivalents included in funds held for clients	126,961	118,094	141,732
Cash, cash equivalents and restricted cash at end of year	160,145	150,474	170,335
Supplemental disclosures of cash flow information:
Cash paid for interest	7,421	3,350	4,739
Cash paid for income taxes, net of income tax refunds	$ 27,815	$ 16,998	$ 25,939