Consolidated Condensed Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 10,733	$ 16,962
Accounts receivable, trade, less allowance of $8,410 and $9,183, respectively	279,716	261,372
Other receivables	27,028	15,168
Inventories and supplies	11,624	12,768
Prepaid taxes, licenses and permits	6,935	15,374
Income taxes receivable	6,538	21,497
Other current assets	38,898	29,987
Total current assets	381,472	373,128
Property and equipment	2,078,229	2,109,991
Less – accumulated depreciation	758,331	747,353
Property and equipment, net	1,319,898	1,362,638
Other non-current assets	61,571	57,237
Total assets	1,762,941	1,793,003
Current liabilities:
Checks issued in excess of cash balances	3,538	0
Accounts payable	72,343	66,618
Current portion of long-term debt	0	20,000
Insurance and claims accruals	84,436	83,404
Accrued payroll	31,029	26,189
Other current liabilities	22,938	18,650
Total current liabilities	214,284	214,861
Long-term debt, net of current portion	75,000	160,000
Other long-term liabilities	14,321	16,711
Insurance and claims accruals, net of current portion	107,230	113,875
Deferred income taxes	301,199	292,769
Commitments and contingencies
Stockholders’ equity:
Common stock, $0.01 par value, 200,000,000 shares authorized; 80,533,536 shares issued; 72,334,476 and 72,166,969 shares outstanding, respectively	805	805
Paid-in capital	103,296	101,035
Retained earnings	1,131,805	1,084,796
Accumulated other comprehensive loss	(13,378)	(16,917)
Treasury stock, at cost; 8,199,060 and 8,366,567 shares, respectively	(171,621)	(174,932)
Total stockholders’ equity	1,050,907	994,787
Total liabilities and stockholders’ equity	$ 1,762,941	$ 1,793,003