Condensed Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating activities:
Net income	$ 48,938,000	$ 31,981,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	65,155,000	45,225,000
Asset impairment	16,184,000	0
Debt issuance amortization	4,421,000	692,000
Original issue discount amortization	561,000	188,000
Deferred income taxes	11,023,000	2,149,000
Deferred revenue	(6,970,000)	15,235,000
(Gain) loss on disposal of property, plant and equipment	(5,619,000)	394,000
Equity-based compensation	13,185,000	11,952,000
Bad debt provision, net of recoveries	387,000	848,000
Other	(4,516,000)	767,000
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	(24,472,000)	(69,400,000)
Inventories	6,040,000	5,207,000
Prepaid expenses and other current assets	1,333,000	2,069,000
Income taxes	(4,757,000)	4,257,000
Accounts payable and accrued expenses	(2,883,000)	25,443,000
Short-term and long-term obligations-vendor incentives	54,632,000	0
Liability for pension and other post-retirement benefits	301,000	454,000
Net cash provided by operating activities	172,943,000	77,461,000
Investing activities:
Capital expenditures	(159,196,000)	(152,087,000)
Capitalized intellectual property costs	(3,863,000)	(1,973,000)
Acquisition of business, net of cash acquired	(742,841,000)	(18,636,000)
Proceeds from sale of property, plant and equipment	26,179,000	12,000
Net cash used in investing activities	(879,721,000)	(172,684,000)
Financing activities:
Dividends paid	(10,132,000)	(10,187,000)
Repurchase of common stock	(90,499,000)	0
Proceeds from options exercised	62,000	547,000
Tax payments related to shares withheld for vested restricted stock and stock units	(4,194,000)	(3,926,000)
Proceeds from long-term debt	1,280,000,000	0
Payments on long-term debt	(493,231,000)	(3,270,000)
Financing fees paid	(37,273,000)	0
Principal payments on capital lease obligations	(165,000)	(631,000)
Net cash provided by (used in) financing activities	644,568,000	(17,467,000)
Net decrease in cash and cash equivalents	(62,210,000)	(112,690,000)
Cash and cash equivalents, beginning of period	384,567,000	711,225,000
Cash and cash equivalents, end of period	322,357,000	598,535,000
Cash paid (received) during the period for:
Interest	22,689,000	12,766,000
Taxes, net of refunds	3,778,000	(1,010,000)
Related party purchases	1,604,000	1,870,000
Non-cash Items:
Equipment received	0	18,185,000
Accrued capital expenditures	21,966,000	7,171,000
Capital lease assumed by third-party	119,000	0
Asset retirement obligation assumed by third-party	$ 2,116,000	$ 0