Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net loss	$ (28,872)	$ (219,095)	$ (176,746)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization	185,267	140,328	109,361
Accretion of asset retirement obligation	40,423	38,892	31,028
Share-based compensation	7,584	7,748	6,082
Non-cash interest expense	9,215	6,857	0
Amortization of deferred financing costs	11,537	10,601	3,481
Loss on extinguishment of debt	0	4,445	49,154
(Gain) loss on derivative instruments	(24,055)	5,587	31,100
Loss (gain) on foreign exchange	715	(3,674)	4,016
Loss on impairment	0	136,210	0
Income from equity affiliates	(5,591)	(5,409)	(3,159)
Distributions from equity affiliates	6,914	7,057	4,042
Deferred income taxes benefit	(46,142)	(17,961)	(642)
Other	(2,705)	(146)	5,597
Changes in operating assets and liabilities:
Receivables	(4,430)	1,987	(403)
Inventories	13,033	1,800	45,335
Accounts payable and accrued expenses	10,505	(5,447)	(24,858)
Interest payable	5,131	(5,569)	(12,905)
Deferred revenue	(7,370)	(13,094)	(12,246)
Other assets and liabilities	13,227	(19,613)	14,738
Asset retirement obligations	(32,452)	(25,942)	(22,622)
Net cash provided by operating activities	151,934	45,562	50,353
Cash flows from investing activities:
Additions to property, plant and equipment	(46,132)	(77,921)	(50,326)
Change in restricted investments	(1,238)	(28,670)	(52,514)
Cash payments in escrow for future acquisitions	0	34,000	(34,000)
Cash payments related to acquisitions and other	(120,992)	(32,529)	(352,635)
Cash acquired related to acquisition, net	0	2,780	8,173
Proceeds from sales of assets	7,695	2,224	38,740
Proceeds from the sale of restricted investments	0	15,532	8,677
Payments related to loan and lease receivables	8,987	21,954	8,039
Receipts from loan and lease receivables	(2,164)	(5,654)	(5,682)
Other	(1,850)	(2,517)	(1,244)
Net cash used in investing activities	(155,694)	(70,801)	(432,772)
Cash flows from financing activities:
Borrowings from long-term debt, net of debt discount	122,250	199,359	1,315,947
Repayments of long-term debt	(70,370)	(148,071)	(955,177)
Borrowings on revolving lines of credit	423,500	201,746	25,000
Repayments on revolving lines of credit	(425,500)	(209,351)	(15,424)
Debt issuance costs and other refinancing costs	(8,784)	(8,132)	(88,144)
Proceeds from issuance of common shares	0	0	56,473
Other	(974)	1,172	31
Net cash provided by financing activities	40,122	36,723	338,706
Effect of exchange rate changes on cash	784	(2,806)	(3,139)
Net increase (decrease) in cash and cash equivalents	37,146	8,678	(46,852)
Cash and cash equivalents, beginning of year	22,936	14,258	61,110
Cash and cash equivalents, end of year	60,082	22,936	14,258
Supplemental disclosures of cash flow information:
Cash paid for interest	96,290	72,972	85,047
Cash paid for income taxes	1,316	434	117
Non-cash transactions:
Accrued purchases of property and equipment	6,496	3,766	11,740
Capital leases and other financing sources	$ 27,355	$ 15,232	$ 15,599