Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 1,189	$ 4,720
Accounts receivable, net	200,644	170,278
Prepaid expenses and other	30,854	28,251
Total current assets	232,687	203,249
Property and Equipment, at cost	1,419,359	1,289,994
Less-accumulated depreciation	594,678	554,214
Net property and equipment	824,681	735,780
Goodwill and Identifiable Intangibles, net	23,346	24,027
Other Noncurrent Assets	5,244	4,259
Total assets	1,085,958	967,315
Current Liabilities:
Accounts payable	71,045	57,438
Wages, vacation and employees’ benefits	46,739	39,748
Claims and insurance accruals	41,326	35,850
Other current liabilities	29,628	19,807
Current portion of long-term debt	16,839	14,083
Total current liabilities	205,577	166,926
Other Liabilities:
Long-term debt, less current portion	138,161	118,833
Deferred income taxes	63,419	59,423
Claims, insurance and other	38,827	39,639
Total other liabilities	240,407	217,895
Commitments and Contingencies
Stockholders’ Equity:
Preferred stock, $0.001 par value, 50,000 shares authorized, none issued and outstanding
Common stock, $0.001 par value, 50,000,000 shares authorized, 25,692,567 and 25,551,617 shares issued and outstanding at June 30, 2018 and December 31, 2017, respectively	26	26
Additional paid-in-capital	252,536	246,454
Deferred compensation trust, 155,714 and 170,310 shares of common stock at cost at June 30, 2018 and December 31, 2017, respectively	(3,494)	(3,486)
Retained earnings	390,906	339,500
Total stockholders’ equity	639,974	582,494
Total liabilities and stockholders’ equity	$ 1,085,958	$ 967,315