Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 80,600	$ 56,995
Receivables:
Trade, less allowances of $500 and $348, respectively	120,702	99,003
Other	7,218	6,971
Prepaid expenses and other	27,320	23,980
Total current assets	235,840	186,949
Property and equipment:
Less accumulated depreciation	(346,665)	(274,199)
Net property and equipment	728,167	682,277
Other noncurrent assets	1,672	1,464
Total assets	965,679	870,690
Current liabilities:
Accounts payable	37,299	20,150
Insurance and claims accruals	45,747	42,014
Accrued and other current liabilities	41,264	31,395
Total current liabilities	124,310	93,559
Deferred income taxes	137,041	125,163
Noncurrent operating lease liabilities	409	291
Total liabilities	261,760	219,013
Stockholders’ equity:
Preferred stock, $.01 par value per share; 2,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $.01 par value per share; 192,000,000 shares authorized; 81,115,132 shares at December 31, 2022, and 83,034,404 shares at December 31, 2021, issued and outstanding	811	830
Additional paid-in capital	47,188	85,718
Retained earnings	655,920	565,129
Total stockholders’ equity	703,919	651,677
Total liabilities and stockholders’ equity	965,679	870,690
Revenue Equipment [Member]
Property and equipment:
Property and equipment	915,866	810,711
Land and Building [Member]
Property and equipment:
Property and equipment	102,877	92,824
Office Equipment [Member]
Property and equipment:
Property and equipment	$ 56,089	$ 52,941