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	$ 75,177	$ 56,039	$ 130,862
Adjustments to reconcile net income to cash provided by operating activities:
Gain on sale of assets held for sale	0	0	(79,318)
Deferred income tax provision, net	2,425	(2,298)	(49)
Provision for credit losses	11	2,130	1,209
Depreciation and amortization	4,500	5,255	6,481
Stock-based compensation expense	13,999	11,595	9,912
Defined benefit pension plans expense	2,157	842	862
Loss on disposal or impairment of assets	(1,929)	1,822	1,084
Noncash lease expense	5,509	5,499	6,282
Loss on equity method investment	2,480	1,681	831
Other	1,036	1,056	1,056
(Increase) decrease in operating assets
Trade receivables, net	(36,960)	(12,863)	(5,360)
Other assets	(9,779)	(4,485)	(9,639)
Increase (decrease) in operating liabilities
Accrued payroll costs	6,337	22,397	4,567
Other liabilities	7,935	20,489	(2,163)
Cash provided by operating activities	72,898	109,159	66,617
Cash flows from investing activities:
Capital expenditures	(6,441)	(6,475)	(10,359)
Equity method investment	(9,000)	(4,000)	(9,000)
Net proceeds from the sale of assets held for sale	23,742	3,548	122,544
Cash provided by (used in) investing activities	8,301	(6,927)	103,185
Cash flows from financing activities:
Proceeds from credit facility	0	35,000	80,100
Payments on credit facility	0	0	(86,900)
Payments on other financing arrangements, payment of contingent consideration liability and other	(308)	(1,177)	(2,222)
Payments of loan financing fees	(1,058)	0	0
Repurchases of common stock	(66,210)	(35,613)	(124,453)
Cash dividends	(20,120)	(16,787)	(16,608)
Cash used in financing activities	(87,696)	(18,577)	(150,083)
Change in cash and cash equivalents	(6,497)	83,655	19,719
Cash and cash equivalents at beginning of year	103,486	19,831	112
Cash and cash equivalents at end of year	96,989	103,486	19,831
Cash paid during the year for:
Income taxes	24,277	21,737	24,935
Operating lease liabilities	7,468	7,330	8,186
Interest, net	2,453	2,574	1,480
Non-Cash Financing and Investing Transactions:
ROU assets obtained from operating leases	5,098	5,695	9,205
Employee stock purchase plan	$ 762	$ 549	$ 558