CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Consolidated Statements of Operations and Comprehensive Income (Loss)
Gas marketing, related costs	$ 39,853	$ 25,312
Change in fair value investments, tax	$ 231	$ 49

Other Comprehensive Income Unrealized Gain Loss In Fair Value Of Investments Tax

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration