CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
OPERATING ACTIVITIES
Net (loss) income	$ (141,246)	$ (99,561)	$ 245,193
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation, amortization and other non-cash charges	221,038	275,413	233,940
Stock-based compensation expense	10,218	9,960	9,074
(Gain) loss on disposition of assets, net	(7,920)	6,417	15,472
Deferred income tax (benefit) provision	(34,209)	(33,013)	12,354
Excess tax benefits for share-based payments	(427)	(1,410)	(4,336)
(Increase) decrease in assets:
Accounts receivable	64,715	401,753	(198,021)
Income taxes receivable	(5,355)	(20,867)	(19,059)
Inventories	20,294	26,667	(29,708)
Prepaid expenses	2,244	161	2
Other current assets	2	(2,881)	(749)
Other non-current assets	(1,851)	1,768	(2,238)
Increase (decrease) in liabilities:
Accounts payable	(6,250)	(62,446)	36,421
Income taxes payable	(2,710)	6,695	944
Accrued payroll and related expenses	(4,540)	(33,143)	13,221
Accrued insurance expenses	(197)	(1,336)	(440)
Accrued state, local and other taxes	256	(3,983)	1,819
Other accrued expenses	5,017	(180)	(775)
Pension liabilities	(1,385)	1,021	2,219
Long-term accrued insurance expenses	(1,811)	1,249	(126)
Other long-term liabilities	(14,179)	1,508	7,550
Net cash provided by operating activities	101,704	473,792	322,757
INVESTING ACTIVITIES
Capital expenditures	(33,938)	(167,426)	(371,502)
Proceeds from sale of assets	12,599	9,843	18,707
Investment in joint venture			(2,554)
Net cash used for investing activities	(21,339)	(157,583)	(355,349)
FINANCING ACTIVITIES
Payment of dividends	(10,861)	(33,602)	(91,608)
Borrowings from notes payable to banks		613,300	1,168,100
Repayments of notes payable to banks		(837,800)	(996,900)
Debt issue costs for notes payable to banks	(35)		(667)
Excess tax benefits for share-based payments	427	1,410	4,336
Cash paid for common stock purchased and retired	(3,257)	(4,093)	(49,597)
Net cash (used for) provided by financing activities	(13,726)	(260,785)	33,664
Net increase in cash and cash equivalents	66,639	55,424	1,072
Cash and cash equivalents at beginning of year	65,196	9,772	8,700
Cash and cash equivalents at end of year	$ 131,835	$ 65,196	$ 9,772