Consolidated Condensed Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 64,742	$ 33,930
Accounts receivable, trade, less allowance of $8,457 and $8,613, respectively	313,524	337,927
Other receivables	22,851	26,545
Inventories and supplies	9,674	10,060
Prepaid taxes, licenses and permits	12,769	16,619
Other current assets	31,894	31,577
Total current assets	455,454	456,658
Property and equipment	2,290,802	2,247,577
Less – accumulated depreciation	776,863	760,015
Property and equipment, net	1,513,939	1,487,562
Other non-current assets	149,439	139,284
Total assets	2,118,832	2,083,504
Current liabilities:
Accounts payable	99,725	97,781
Current portion of long-term debt	75,000	75,000
Insurance and claims accruals	69,561	67,304
Accrued payroll	33,728	40,271
Income taxes payable	18,137	6,693
Other current liabilities	26,448	23,311
Total current liabilities	322,599	310,360
Long-term debt, net of current portion	50,000	50,000
Other long-term liabilities	17,129	10,911
Insurance and claims accruals, net of current portion	219,970	214,030
Deferred income taxes	233,745	233,450
Commitments and contingencies
Stockholders’ equity:
Common stock, $0.01 par value, 200,000,000 shares authorized; 80,533,536 shares issued; 69,888,102 and 70,441,973 shares outstanding, respectively	805	805
Paid-in capital	107,928	107,455
Retained earnings	1,443,542	1,413,746
Accumulated other comprehensive loss	(15,560)	(16,073)
Treasury stock, at cost; 10,645,434 and 10,091,563 shares, respectively	(261,326)	(241,180)
Total stockholders’ equity	1,275,389	1,264,753
Total liabilities and stockholders’ equity	$ 2,118,832	$ 2,083,504