Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net earnings	$ 16,415	$ 40,211
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	79,468	65,921
Equity-based compensation expense	2,523	9,826
Deferred tax expense	14,602	12,329
Employee benefit plans	(2,999)	(500)
Gain (Loss) on Disposition of Assets	3,755	30
Increase (Decrease) in Other Operating Assets and Liabilities, Net	874	484
Changes in working capital, net	43,846	4,045
Change in taxes receivable, net	(4,869)	7,217
Other Operating Activities, Cash Flow Statement	(1,439)	(680)
Net cash provided by operating activities	152,176	138,883
CASH FLOWS FROM INVESTING ACTIVITIES
Additions to plant and equipment	(136,650)	(105,514)
Payments for (Proceeds from) Other Investing Activities	753	250
Net cash used for investing activities	(135,897)	(105,264)
CASH FLOWS FROM FINANCING ACTIVITIES
Purchase of treasury stock	(4,875)	(51,528)
Proceeds from (Repayments of) Short-term Debt	185,000	944,844
Payments of Debt Issuance Costs	(210,000)	(931,832)
Payment of tax withholdings on equity-based payment arrangements	(790)
Proceeds from (Payments for) Other Financing Activities	(927)	(382)
Net cash (used for) provided by financing activities	(30,802)	(38,898)
Decrease in cash and cash equivalents	(14,523)	(5,279)
Cash at beginning of period	23,001	5,610
Cash at end of period	8,478	331
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for interest, net of amounts capitalized	27,867	27,240
Cash paid for income taxes	2,367	16,050
Cash received from income tax refunds	5,988	10,543
Changes in accrued plan and equipment	2,173	3,834
Non-cash additions to plant, property, and equipment	$ 4,500	$ 0