Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
OPERATING ACTIVITIES:
Net (loss) / income	$ 3,874	$ 21,536
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	41,936	40,974
Bad debt expense	329	694
Stock compensation-net of excess tax benefits	430	736
Provision for deferred income taxes	763	6,081
Recognized loss / (gain) on marketable equity securities	7,484	(2,728)
(Gain) Loss on sale or disposition of equipment	(71)	362
Changes in operating assets and liabilities:
Accounts receivable	(8,409)	2,312
Prepaid expenses, deposits, inventories, and other assets	1,064	2,169
Income taxes payable	(52)	(299)
Trade accounts payable	22,112	3,218
Accrued expenses and other liabilities	(16,354)	1,340
Net cash provided by operating activities	53,106	76,395
INVESTING ACTIVITIES:
Purchases of property and equipment	(39,763)	(68,046)
Proceeds from disposition of equipment	13,502	12,714
Sales of marketable equity securities	860	1,645
Purchases of marketable equity securities, net of return of capital	(3,982)	(128)
Net cash used in investing activities	(29,383)	(53,815)
FINANCING ACTIVITIES:
Borrowings under line of credit	365,263	444,362
Repayments under line of credit	(371,182)	(445,318)
Borrowings of long-term debt	17,640	45,557
Repayments of long-term debt	(38,872)	(51,253)
Borrowings under margin account	7,037	387
Repayments under margin account	(1,806)	(2,676)
Repurchases of common stock	(1,793)	(13,616)
Net cash used in financing activities	(23,713)	(22,557)
NET INCREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	10	23
CASH, CASH EQUIVALENTS AND RESTRICTED CASH -Beginning of period	318	282
CASH, CASH EQUIVALENTS AND RESTRICTED CASH -End of period	328	305
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION-
Interest	6,544	6,258
Income taxes	159	601
NONCASH INVESTING AND FINANCING ACTIVITIES-
Purchases of property and equipment included in accounts payable	$ 3,944	$ 5,711