Supplemental Cash Flow Information (Supplemental Cash Flow Disclosures) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Supplemental Cash Flow Elements [Abstract]
Interest Paid, Excluding Capitalized Interest, Operating Activities	$ 16,451	$ 14,855
Change in capital expenditure payables and accruals	74,666	(9,677)
Divestiture date fair value of contingent consideration arrangement	0	(7,880)
Share-based Compensation, Capitalized Amount	1,903	708
Costs Incurred, Asset Retirement Obligation Incurred	3,226	142
Non Cash Gain Loss On Extinguishment Of Debt	$ 0	$ 2,666

Change in accrued capital expenditures and capital expenditures in accounts payable

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- Definition

The fair value of the contingent consideration on the date of the divestiture

+ References

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- Definition

The non-cash portion of (gain) loss on the early extinguishment of debt.

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- Definition

Amount of asset retirement obligations (ARO) costs incurred (whether capitalized or charged to expense) during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Represents the compensation cost capitalized during the period arising from equity-based compensation arrangements (for example, shares of stock, units, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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- Definition

Amount of cash paid for interest, excluding capitalized interest, classified as operating activity. Includes, but is not limited to, payment to settle zero-coupon bond for accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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