Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net (loss) income	$ (37,300)	$ 26,909
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization	36,567	37,015
Accretion of asset retirement obligation and receivable	11,295	7,007
Share-based compensation	1,347	2,580
Non-cash interest expense	2,296	2,269
Amortization of deferred financing costs	2,626	3,214
(Gain) loss on derivative instruments	(2,384)	2,600
Loss on foreign exchange	467	1,387
Income from equity affiliates	(1,520)	(1,293)
Distributions from equity affiliates	1,671	1,451
Deferred income tax benefit	(465)	(47,973)
Other	(1,474)	(2,926)
Changes in operating assets and liabilities:
Receivables	12,250	(10,052)
Inventories	5,156	(7,323)
Accounts payable and accrued expenses	(21,905)	7,698
Interest payable	(7,787)	(5,600)
Deferred revenue	2,005	3,389
Other assets and liabilities	7,104	(18,247)
Asset retirement obligation	(10,659)	18,449
Net cash provided by operating activities	(710)	20,554
Cash flows from investing activities:
Additions to property, plant and equipment	(7,210)	(5,548)
Change in restricted investments	(1,171)	(3,172)
Cash payments related to acquisitions and other	(3,580)	(126,865)
Proceeds from sales of assets	466	1,626
Receipts from loan and lease receivables	50,488	1,620
Payments related to loan and lease receivables	0	(312)
Other	(293)	79
Net cash provided by (used in) investing activities	38,700	(132,572)
Cash flows from financing activities:
Borrowings from long-term debt, net of debt discount	0	121,225
Repayments of long-term debt	(22,368)	(9,018)
Borrowings on revolving lines of credit	123,200	77,500
Repayments of revolving lines of credit	(123,200)	(79,500)
Debt issuance costs and other refinancing costs	0	(2,927)
Other	(178)	(262)
Net cash (used in) provided by financing activities	(22,546)	107,018
Effect of exchange rate changes on cash	(88)	(182)
Net increase (decrease) in cash and cash equivalents	15,356	(5,182)
Cash and cash equivalents, beginning of period	60,082	22,936
Cash and cash equivalents, end of period	75,438	17,754
Supplemental disclosures of cash flow information:
Cash paid for interest	31,951	30,397
Non-cash transactions:
Accrued purchases of property and equipment	2,969	2,279
Capital leases and other financing sources	$ 480	$ 0