Consolidated Condensed Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 22,003	$ 15,791
Receivables:
Trade, net	85,549	74,886
Other	7,190	6,131
Prepaid expenses and other	19,876	19,810
Total current assets	134,618	116,618
Property and equipment:
Revenue equipment, buildings and land, office equipment and other	805,723	783,648
Accumulated depreciation	(218,071)	(211,728)
Net property and equipment	587,652	571,920
Other assets	2,169	1,865
Total assets	724,439	690,403
Current liabilities:
Accounts payable and accrued liabilities	45,782	38,100
Insurance and claims accruals	25,574	26,177
Total current liabilities	71,356	64,277
Deferred income taxes	103,841	100,626
Total liabilities	175,197	164,903
Stockholders’ equity:
Preferred stock, $.01 par value per share; 2,000,000 shares authorized; no shares issued and outstanding
Common stock, $.01 par value per share; 192,000,000 shares authorized; 54,659,074 shares at June 30, 2018, and 54,533,455 shares at December 31, 2017, issued and outstanding	547	545
Additional paid-in capital	78,366	76,413
Retained earnings	470,329	448,542
Total stockholders’ equity	549,242	525,500
Total liabilities and stockholders’ equity	$ 724,439	$ 690,403