CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019		Mar. 31, 2018
OPERATING ACTIVITIES
Net (loss) income	$ (739)		$ 52,130
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation, amortization and other non-cash charges	43,062		38,148
Stock-based compensation expense	2,452		2,555
Gain on disposition of assets, net	(3,504)		(1,363)
Deferred income tax benefit	(7,446)		(1,034)
(Increase) decrease in assets:
Accounts receivable	4,400		(6,953)
Income taxes receivable	27,219		10,300
Inventories	5,731		(6,215)
Prepaid expenses	423		2,039
Other current assets	354		(1,535)
Other non-current assets	(2,844)		295
Increase (decrease) in liabilities:
Accounts payable	3,666		11,990
Income taxes payable	(1,187)		4,786
Accrued payroll and related expenses	433		3,169
Accrued insurance expenses	179		374
Accrued state, local and other taxes	1,647		970
Other accrued expenses	166		169
Pension liabilities	3,145		(588)
Long-term accrued insurance expenses	637		935
Other long-term liabilities	(648)		(509)
Net cash provided by operating activities	77,146		109,663
INVESTING ACTIVITIES
Capital expenditures	(62,280)		(50,482)
Proceeds from sale of assets	6,070		3,119
Net cash used for investing activities	(56,210)		(47,363)
FINANCING ACTIVITIES
Payment of dividends	(21,486)		(21,657)
Cash paid for common stock purchased and retired	(2,698)		(30,710)
Net cash used for financing activities	(24,184)		(52,367)
Net (decrease) increase in cash and cash equivalents	(3,248)		9,933
Cash and cash equivalents at beginning of period	116,262	[1]	91,050
Cash and cash equivalents at end of period	113,014		100,983
Supplemental cash flows disclosure:
Income taxes (refund) paid, net	(18,938)		292
Supplemental disclosure of noncash investing activities:
Capital expenditures included in accounts payable	$ 17,634		$ 18,823

[1] Note 1