CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income		$ 56,039	$ 130,862	$ 57,980
Adjustments to reconcile net income to cash provided by operating activities:
Gain on sale of assets held for sale		0	(79,318)
Gain on sale of assets held for sale				0
Deferred income tax provision, net		(2,298)	(49)	989
Provision for bad debts		2,130	1,209	1,820
Depreciation and amortization		5,255	6,481	8,265
Stock-based compensation expense		11,595	9,912	8,797
Defined benefit pension plans expense		842	862	1,821
Loss on deferred compensation plan investments, net		702	245	563
Loss on disposal or impairment of assets		1,822	1,084	38
Noncash lease expense		5,499	6,282
Loss on equity method investment		1,681	831	0
Contingent consideration liability remeasurement and other		354	811	350
(Increase) decrease in operating assets
Trade receivables, net		(12,863)	(5,360)	(10,851)
Other assets		(4,485)	(9,639)	5,741
Increase (decrease) in operating liabilities
Accrued payroll costs		22,397	4,567	1,350
Other liabilities		20,489	(2,163)	10,860
Cash provided by operating activities		109,159	66,617	87,723
Cash flows from investing activities:
Capital expenditures		(6,475)	(10,359)	(5,170)
Equity method investment		(4,000)	(9,000)	0
Net proceeds from the sale of assets held for sale		3,548	122,544	1,000
Cash provided by (used in) investing activities		(6,927)	103,185	(4,170)
Cash flows from financing activities:
Proceeds from credit facility		35,000	80,100	450,400
Payments on credit facility		0	(86,900)	(495,123)
Payments on other financing arrangements, payment of contingent consideration liability and other		(1,177)	(2,222)	(2,039)
Repurchases of common stock		(35,613)	(124,453)	(22,187)
Cash dividends		(16,787)	(16,608)	(14,871)
Cash used in financing activities		(18,577)	(150,083)	(83,820)
Change in cash and cash equivalents		83,655	19,719	(267)
Cash and cash equivalents at beginning of year		19,831	112	379
Cash and cash equivalents at end of year		103,486	19,831	112
Cash paid during the year for:
Income taxes	[1]	21,737	24,935	13,442
Operating lease liabilities		7,330	8,186
Interest, net		2,574	1,480	3,814
Non-Cash Financing and Investing Transactions:
ROU assets obtained from operating leases		5,695	9,205
Employee stock purchase plan		549	558	549
Unsettled repurchases of common stock		$ 0	$ 0	556
Proceeds from income tax refunds				$ 6,800

[1] During the year ended December 31, 2018, cash provided by operating activities included the receipt of an income tax refund in the amount of $6.8 million.