Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 462,564	$ 401,430
Short-term investments	254,433	330,274
Customer receivables, less allowances of $9,855 and $8,979, respectively	567,474	444,653
Income taxes receivable	19,218
Other receivables	12,410	9,569
Prepaid expenses and other current assets	67,688	57,413
Total current assets	1,383,787	1,243,339
Property and equipment:
Revenue equipment	2,146,205	1,885,649
Land and structures	2,463,949	2,218,290
Other fixed assets	512,340	475,264
Leasehold improvements	13,131	12,226
Total property and equipment	5,135,625	4,591,429
Less: Accumulated depreciation	(1,919,939)	(1,677,398)
Net property and equipment	3,215,686	2,914,031
Other assets	222,071	212,040
Total assets	4,821,544	4,369,410
Current liabilities:
Accounts payable	82,519	68,511
Compensation and benefits	257,905	191,303
Claims and insurance accruals	61,822	53,092
Other accrued liabilities	61,988	51,513
Income taxes payable		8,711
Total current liabilities	464,234	373,130
Long-term debt	99,947	99,931
Other non-current liabilities	328,838	349,851
Deferred income taxes	248,718	220,210
Total long-term liabilities	677,503	669,992
Total liabilities	1,141,737	1,043,122
Commitments and contingent liabilities
Shareholders’ equity
Common stock - $0.10 par value, 280,000,000 shares authorized, 115,011,172 and 117,057,696 shares outstanding at December 31, 2021 and December 31, 2020, respectively.	11,501	11,706
Capital in excess of par value	174,445	226,451
Retained earnings	3,493,861	3,088,131
Total shareholders’ equity	3,679,807	3,326,288
Total liabilities and shareholders’ equity	$ 4,821,544	$ 4,369,410