Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Operating activities
Net income (loss)	$ (28,338)	$ 16,120
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Deferred income tax provision (benefit)	(10,670)	3,764
Depreciation and amortization	60,174	62,049
(Gains) losses on sale of equipment	(3,341)	3,047
Share based compensation	3,998	5,294
Other	203	546
Unrealized loss (gain) on equity investment	9,989	(8,129)
Changes in operating assets and liabilities:
Receivables	(14,154)	(38,064)
Prepaid insurance and licenses	(7,838)	(7,486)
Operating supplies	(648)	(3,420)
Other assets	(3,677)	(8,284)
Accounts payable and other accrued liabilities	22,811	36,762
Accrued wages and benefits	(3,099)	8,105
Net cash provided by operating activities	25,410	70,304
Investing activities
Payments for purchases of property and equipment	(147,643)	(141,068)
Proceeds from sales of property and equipment	33,877	70,016
Net cash used in investing activities	(113,766)	(71,052)
Financing activities
Borrowings under lines of credit	382,307	235,612
Payments under lines of credit	(314,241)	(210,612)
Borrowings under long-term debt	85,674	83,959
Payments of long-term debt and finance leases	(67,930)	(110,759)
Payments of financing costs		(100)
Tax withholding related to net share settlement of restricted stock awards	(431)	(1,211)
Proceeds from issuance of common stock under ESPP	1,330	1,285
Proceeds from long-term consideration for sale of subsidiary	483	460
Book overdraft	(3,160)	2,604
Net cash provided by financing activities	84,032	1,238
Net change in cash and cash equivalents	(4,324)	490
Cash and cash equivalents
Beginning of year	5,695	5,505
End of period	1,371	5,995
Supplemental disclosure of cash flow information
Cash paid during the year for interest	12,344	10,281
Cash paid during the year for income taxes	1,214	1,213
Supplemental disclosure of significant noncash investing and financing activities
Uncollected proceeds from asset sales	333
Property and equipment amounts accrued in accounts payable	1,541	3,887
Finance lease additions	$ 1,118	$ 5,572