Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Operating activities:
Net income (loss) attributable to NextDecade Corporation	$ 181,844		$ 34,208	$ (41,146)
Adjustment to reconcile net loss to net cash used in operating activities
Depreciation	42	$ 41	117	129
Share-based compensation expense			22,055	3,555
Loss on common stock warrant liabilities	(3,302)	2,773	2,520	7,192
Derivative gain	(240,265)	0	(152,816)	0
Net cash provided by settlement of derivative instruments			1,160	0
Amortization of right-of-use assets			570	522
Gain on sale of assets			(6,020)	0
Amortization of debt issuance costs			25,670	0	$ 0
Interest Expense			2,929	0
Amortization of other non-current assets			0	354
Changes in operating assets and liabilities:
Prepaid expenses and other current assets			(1,121)	(460)
Accounts payable			3,313	294
Operating lease liabilities			330	(482)
Accrued expenses and other liabilities			14,458	2,081
Net cash used in operating activities			(52,627)	(27,961)
Investing activities:
Acquisition of property, plant and equipment			(996,467)	(5,673)
Acquisition of other non-current assets			(13,971)	(5,343)
Net cash used in investing activities			(1,010,438)	(11,016)
Financing activities:
Proceeds from debt issuance			1,409,000	0
Proceeds from sale of equity in Intermediate Holdings			278,962	0
Proceeds from sale of Rio Bravo Pipeline, LLC			4,393	0
Proceeds from sale of Series C Convertible Preferred Stock			0	10,500
Proceeds from sale of common stock			254,400	115,000
Debt and equity issuance costs			(490,960)	(2)
Preferred stock dividends			(53)	(38)
Shares repurchased related to share-based compensation			(9,607)	(2,812)
Net cash provided by financing activities			1,446,135	122,648
Net increase in cash and cash equivalents			383,070	83,671
Cash and cash equivalents – beginning of period			62,789	25,552	25,552
Cash and cash equivalents – end of period	445,859	109,223	445,859	109,223	62,789
Balance per Consolidated Balance Sheets:
Cash and cash equivalents	50,847		50,847		62,789
Restricted cash	395,012		395,012
Total cash, cash equivalents and restricted cash	$ 445,859	$ 109,223	$ 445,859	$ 109,223	$ 62,789