Consolidated Condensed Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 46,420	$ 33,930
Accounts receivable, trade, less allowance of $8,409 and $8,613, respectively	331,239	337,927
Other receivables	23,635	26,545
Inventories and supplies	10,282	10,060
Prepaid taxes, licenses and permits	8,008	16,619
Other current assets	33,717	31,577
Total current assets	453,301	456,658
Property and equipment	2,312,594	2,247,577
Less – accumulated depreciation	787,214	760,015
Property and equipment, net	1,525,380	1,487,562
Other non-current assets	149,936	139,284
Total assets	2,128,617	2,083,504
Current liabilities:
Accounts payable	92,713	97,781
Current portion of long-term debt	0	75,000
Insurance and claims accruals	70,483	67,304
Accrued payroll	37,432	40,271
Other current liabilities	27,942	30,004
Total current liabilities	228,570	310,360
Long-term debt, net of current portion	390,000	50,000
Other long-term liabilities	17,424	10,911
Insurance and claims accruals, net of current portion	225,997	214,030
Deferred income taxes	234,282	233,450
Stockholders’ equity:
Common stock, $0.01 par value, 200,000,000 shares authorized; 80,533,536 shares issued; 69,195,003 and 70,441,973 shares outstanding, respectively	805	805
Paid-in capital	110,102	107,455
Retained earnings	1,219,529	1,413,746
Accumulated other comprehensive loss	(15,140)	(16,073)
Treasury stock, at cost; 11,338,533 and 10,091,563 shares, respectively	(282,952)	(241,180)
Total stockholders’ equity	1,032,344	1,264,753
Total liabilities and stockholders’ equity	$ 2,128,617	$ 2,083,504