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	$ 70,887	$ 78,299	$ 70,714
Adjustments to reconcile net income to net cash provided by operating activities:
Loss (gain) on sale of operations, net of tax	(5,995)	509	(417)
Depreciation and amortization expense	27,078	23,139	22,345
Bad debt expense, net of recoveries	3,054	4,409	2,415
Adjustment to contingent earnout liability, net	2,367	(629)	1,599
Deferred income taxes	9,234	(770)	9,695
Stock-based compensation expense	11,407	8,869	7,254
Other, net	(126)	485	1,077
Changes in assets and liabilities, net of acquisitions and divestitures:
Accounts receivable, net	(17,040)	6,714	(15,529)
Other assets	3,474	1,472	907
Accounts payable	3,312	(8,800)	9,829
Income taxes payable	(4,108)	(236)	(5,460)
Accrued personnel costs	24,525	19,788	(4,093)
Other liabilities	3,109	13,667	(1,813)
Net cash provided by continuing operations	131,178	146,916	98,523
Operating cash flows used in discontinued operations	(24)	(71)	(338)
Net cash provided by operating activities	131,154	146,845	98,185
Cash flows from investing activities:
Business acquisitions and purchases of client lists, net of cash acquired	(66,734)	(71,430)	(11,744)
Purchases of client fund investments	(26,980)	(3,447)	(27,216)
Proceeds from the sales and maturities of client fund investments	14,877	37,487	23,958
Proceeds from sales of divested operations	9,710	711	3
Additions to property and equipment	(8,984)	(11,576)	(13,873)
Other, net	(3,899)	1,849	1,187
Net cash used in investing activities	(82,010)	(46,406)	(27,685)
Cash flows from financing activities:
Proceeds from bank debt	852,100	592,354	648,648
Payment of bank debt	(804,800)	(589,854)	(678,648)
Payment for acquisition of treasury stock	(100,487)	(58,536)	(27,163)
Changes in client funds obligations	(8,874)	(13,747)	10,069
Payment of contingent consideration of acquisitions	(14,084)	(12,859)	(17,457)
Proceeds from exercise of stock options	7,311	6,486	10,608
Other, net	(171)	(453)	(606)
Net cash used in financing activities	(69,005)	(76,609)	(54,549)
Net increase (decrease) in cash, cash equivalents and restricted cash	(19,861)	23,830	15,951
Cash, cash equivalents and restricted cash at beginning of year	170,335	146,505	130,554
Cash, cash equivalents and restricted cash at end of year	150,474	170,335	146,505
Reconciliation of cash, cash equivalents and restricted cash to the Consolidated Balance Sheets
Cash and cash equivalents	1,997	4,652	567
Restricted cash	30,383	23,951	29,595
Cash equivalents included in funds held for clients	118,094	141,732	116,343
Cash, cash equivalents and restricted cash at end of year	150,474	170,335	146,505
Supplemental disclosures of cash flow information:
Cash paid for interest	3,350	4,739	5,556
Cash paid for income taxes, net of income tax refunds	$ 16,998	$ 25,939	$ 17,497