Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 7,600	$ 14,612
Trade accounts receivable, net	1,051,698	920,767
Other receivables, net	274,511	283,499
Inventories	21,977	20,688
Prepaid expenses	147,195	99,162
Total current assets	1,502,981	1,338,728
Property and equipment, at cost:
Revenue and service equipment	4,716,860	4,158,878
Land	49,486	47,231
Structures and improvements	238,202	202,730
Furniture and office equipment	324,695	261,625
Total property and equipment	5,329,243	4,670,464
Less accumulated depreciation	1,884,132	1,687,133
Net property and equipment	3,445,111	2,983,331
Goodwill	40,087	39,764
Other intangible assets, net	65,070	73,691
Other assets	38,398	29,835
Total assets	5,091,647	4,465,349
Current liabilities:
Current portion of long-term debt	250,706
Trade accounts payable	709,736	598,594
Claims accruals	275,139	251,980
Accrued payroll	80,922	42,382
Other accrued expenses	35,845	28,888
Total current liabilities	1,352,348	921,844
Long-term debt	898,398	1,085,649
Other long-term liabilities	96,056	76,661
Deferred income taxes	643,461	541,870
Total liabilities	2,990,263	2,626,024
Commitments and contingencies (Note 10)
Stockholders’ equity:
Preferred stock, $100 par value. 10 million shares authorized; none outstanding
Common stock, $.01 par value. 1 billion shares authorized; (167,099,432 shares issued at December 31, 2018 and 2017, of which 108,710,825 shares and 109,753,008 shares were outstanding at December 31, 2018 and 2017, respectively)	1,671	1,671
Additional paid-in capital	340,457	310,811
Retained earnings	4,188,435	3,803,844
Treasury stock, at cost (58,388,607 shares at December 31, 2018, and 57,346,424 shares at December 31, 2017)	(2,429,179)	(2,277,001)
Total stockholders’ equity	2,101,384	1,839,325
Total liabilities and stockholders' equity	$ 5,091,647	$ 4,465,349