Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
CURRENT ASSETS
Cash and cash equivalents	$ 148,212	$ 113,852
Trade receivables, net of $1.1 million allowance in 2021 and 2020, respectively	60,568	55,577
Prepaid tires	8,758	8,241
Other current assets	9,129	15,342
Total current assets	226,667	193,012
PROPERTY AND EQUIPMENT
Land and land improvements	83,361	77,525
Buildings	87,713	86,712
Furniture and fixtures	5,034	4,807
Shop and service equipment	14,551	14,380
Revenue equipment	562,501	590,153
Construction in progress	6,908	5,783
Property, Plant and Equipment, Gross	760,068	779,360
Less accumulated depreciation	247,235	240,080
Property and equipment, net	512,833	539,280
GOODWILL	168,295	168,295
OTHER INTANGIBLES, NET	24,148	24,746
OTHER ASSETS	17,478	17,679
Deferred Income Taxes, Net	0	8,164
Assets	949,421	951,176
CURRENT LIABILITIES
Accounts payable and accrued liabilities	16,954	12,751
Compensation and benefits	25,607	22,422
Insurance accruals	15,482	15,837
Other Accrued Liabilities	19,053	18,557
Accrued Income Taxes, Current	6,960	1,475
Total current liabilities	84,056	71,042
LONG-TERM LIABILITIES
Income taxes payable	5,564	5,801
Deferred Tax and Other Liabilities, Noncurrent	92,450	104,004
Insurance accruals less current portion	44,934	45,995
Total long-term liabilities	142,948	155,800
COMMITMENTS AND CONTINGENCIES (Note 13)
STOCKHOLDERS' EQUITY
Preferred stock, par value $.01; authorized 5,000 shares; none issued	0	0
Capital stock, common, $.01 par value; authorized 395,000 shares; issued 90,689 in 2021 and 2020; outstanding 79,905 and 80,653 in 2021 and 2020, respectively	907	907
Additional paid-in capital	4,476	4,330
Retained earnings	903,105	890,970
Treasury stock, at cost; 10,784 and 10,036 shares in 2021 and 2020, respectively	(186,071)	(171,873)
Stockholders' Equity Attributable to Parent	722,417	724,334
Liabilities and Stockholders' Equity	$ 949,421	$ 951,176