Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 5,542	$ 5,961
Trade accounts receivable, net	671,398	653,795
Prepaid expenses and other	91,231	220,374
Total current assets	768,171	880,130
Property and equipment, at cost	3,957,722	3,719,757
Less accumulated depreciation	1,287,213	1,237,225
Net property and equipment	2,670,509	2,482,532
Other assets	80,584	34,455
Total assets	$ 3,519,264	3,397,117
Current liabilities:
Current portion of long-term debt		250,000
Trade accounts payable	$ 355,671	325,838
Claims accruals	100,649	96,719
Accrued payroll	69,447	80,547
Other accrued expenses	18,281	17,966
Total current liabilities	544,048	771,070
Long-term debt	993,353	683,539
Other long-term liabilities	59,646	59,561
Deferred income taxes	673,030	678,424
Stockholders' equity	1,249,187	1,204,523
Total liabilities and stockholders' equity	$ 3,519,264	$ 3,397,117