Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current Assets:
Cash and cash equivalents	$ 360	$ 124
Accounts receivable, net	142,331	124,222
Prepaid expenses and other	29,450	34,643
Total current assets	172,141	158,989
Property and Equipment, at cost	1,107,001	995,514
Less-accumulated depreciation	481,088	456,335
Net property and equipment	625,913	539,179
Goodwill and Identifiable Intangibles, net	26,232	26,986
Other Noncurrent Assets	4,621	4,039
Total assets	828,907	729,193
Current Liabilities:
Accounts payable	49,679	54,754
Wages, vacation and employees’ benefits	33,619	27,834
Other current liabilities	45,014	46,360
Current portion of long-term debt	16,627	12,432
Total current liabilities	144,939	141,380
Other Liabilities:
Long-term debt, less current portion	122,747	56,540
Deferred income taxes	71,673	67,417
Claims, insurance and other	35,352	35,967
Total other liabilities	229,772	159,924
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, 25,207,381 and 25,141,799 shares issued and outstanding at June 30, 2016 and December 31, 2015, respectively	25	25
Additional paid-in-capital	233,200	230,593
Deferred compensation trust, 170,027 and 165,971 shares of common stock at cost at June 30, 2016 and December 31, 2015, respectively	(3,252)	(3,102)
Retained earnings	224,223	200,373
Total stockholders’ equity	454,196	427,889
Total liabilities and stockholders’ equity	$ 828,907	$ 729,193