Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
OPERATING ACTIVITIES:
Net Income	$ 3,892,000	$ 6,927,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	21,156,000	18,845,000
Bad debt expense	118,000	272,000
Sale leaseback deferred gain amortization		(112,000)
Stock compensation-net of excess tax benefits	284,000	196,000
Provision for deferred income taxes	2,325,000	4,197,000
Reclassification of unrealized loss on marketable equity securities	27,000	532,000
Recognized (gain) loss on marketable equity securities	(2,145,000)	89,000
Loss (gain) on sale or disposition of equipment	130,000	(3,002,000)
Changes in operating assets and liabilities:
Accounts receivable	(1,010,000)	(11,633,000)
Prepaid expenses, deposits, inventories, and other assets	3,083,000	1,953,000
Income taxes refundable	27,000	2,223,000
Trade accounts payable	(1,938,000)	8,951,000
Accrued expenses and other liabilities	1,403,000	(1,299,000)
Net cash provided by operating activities	27,352,000	28,139,000
INVESTING ACTIVITIES:
Purchases of property and equipment	(14,372,000)	(40,390,000)
Proceeds from disposition of equipment	5,507,000	18,962,000
Change in restricted cash	(1,093,000)	(4,271,000)
Sales of marketable equity securities	3,079,000	279,000
Purchases of marketable equity securities, net of return of capital	13,000	(860,000)
Net cash used in investing activities	(6,866,000)	(26,280,000)
FINANCING ACTIVITIES:
Borrowings under line of credit	218,678,000	254,740,000
Repayments under line of credit	(220,543,000)	(259,085,000)
Borrowings of long-term debt	7,821,000	43,554,000
Repayments of long-term debt	(21,786,000)	(21,413,000)
Borrowings under margin account	81,000	993,000
Repayments under margin account	(3,604,000)	(838,000)
Repurchases of common stock	(1,193,000)	(19,895,000)
Exercise of stock options	112,000	74,000
Net cash used in financing activities	(20,434,000)	(1,870,000)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	52,000	(11,000)
CASH AND CASH EQUIVALENTS-Beginning of period	137,000	157,000
CASH AND CASH EQUIVALENTS-End of period	189,000	146,000
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION-
Interest	1,931,000	1,713,000
Income taxes	106,000	229,000
NONCASH INVESTING AND FINANCING ACTIVITIES-
Purchases of property and equipment included in accounts payable	$ 2,939,000	$ 4,960,000