Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents (Note 9)	$ 32,895	$ 162,675
Accounts receivable	137,217	126,853
Inventories	10,109	7,095
Prepaid income taxes	17,377	6,603
Prepaid expenses	32,688	26,177
Total current assets	230,286	329,403
Investments of deferred compensation plans held in trust (Notes 14 and 16)	98,884	88,811
Properties and equipment, at cost, less accumulated depreciation (Note 12)	193,680	187,820
Lease right of use asset (Note 13)	125,048	123,448
Identifiable intangible assets less accumulated amortization (Note 6)	108,096	118,085
Goodwill	578,591	578,585
Other assets	8,138	8,759
Total Assets	1,342,723	1,434,911
Current liabilities
Accounts payable	73,024	54,234
Income taxes	41	9,464
Accrued insurance	55,918	54,703
Accrued compensation	95,598	91,282
Accrued legal	872	10,632
Short-term lease liability (Note 13)	37,913	36,200
Other current liabilities	39,033	42,593
Total current liabilities	302,399	299,108
Deferred income taxes (Note 11)	23,183	20,664
Long-term debt (Note 3)	185,000
Deferred compensation liabilities (Note 14)	98,597	88,456
Long-term lease liability (Note 13)	100,629	99,210
Other liabilities	9,642	26,273
Total Liabilities	719,450	533,711
Commitments and contingencies (Note 17)
STOCKHOLDERS' EQUITY
Capital stock - authorized 80,000,000 shares $1 par; issued 36,513,857shares (2020 - 36,258,638 shares)	36,514	36,259
Paid-in capital	1,044,341	961,404
Retained earnings	1,970,311	1,723,777
Treasury stock - 21,601,325 shares (2020 - 20,351,562 shares), at cost	(2,430,094)	(1,822,579)
Deferred compensation payable in Company stock (Note 14)	2,201	2,339
Total Stockholders' Equity	623,273	901,200
Total Liabilities and Stockholders' Equity	$ 1,342,723	$ 1,434,911