Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating activities:
Net income (loss)	$ 31,981	$ (22,775)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization	45,225	29,765
Debt issuance amortization	692	696
Original issue discount amortization	188	192
Deferred income taxes	2,149	(18,075)
Deferred revenue	15,235	(3,255)
Loss on disposal of property, plant and equipment	394	29
Equity-based compensation	11,952	5,355
Bad debt provision	848	101
Other	767	1,211
Changes in operating assets and liabilities, net effects of acquisitions:
Accounts receivable	(69,400)	4,312
Inventories	5,207	(2,154)
Prepaid expenses and other current assets	2,069	1,022
Income taxes	4,257	5,438
Accounts payable and accrued liabilities	32,331	(1,584)
Accrued interest	(108)	(1)
Liability for pension and other post-retirement benefits	454	1,044
Net cash provided by operating activities	84,241	1,321
Investing activities:
Capital expenditures	(158,867)	(23,388)
Capitalized intellectual property costs	(1,973)	0
Maturities of short-term investments	0	21,872
Acquisition of business, net of cash acquired	18,636	0
Proceeds from sale of property, plant and equipment	12	66
Net cash used in investing activities	(179,464)	(1,450)
Financing activities:
Dividends paid	(10,187)	(6,732)
Issuance of common stock	0	200,000
Common stock issuance costs	0	(13,798)
Proceeds from options exercised	547	1,299
Tax payments related to shares withheld for vested restricted stock	(3,926)	(959)
Repayment of long-term debt	(3,270)	(2,550)
Principal payments on capital lease obligations	(631)	0
Net cash (used in) provided by financing activities	(17,467)	177,260
Net increase (decrease) in cash and cash equivalents	(112,690)	177,131
Cash and cash equivalents, beginning of period	711,225	277,077
Cash and cash equivalents, end of period	598,535	454,208
Cash paid (received) during the period for:
Interest	12,766	10,571
Taxes, net of refunds	(1,010)	(5,299)
Non-cash Items:
Equipment received	$ 18,185	$ 0