Cover Page - shares	3 Months Ended
	Mar. 31, 2024	May 03, 2024
Cover [Abstract]
Document Type	10-Q/A
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	001-36842
Entity Registrant Name	NEXTDECADE CORPORATION
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-5723951
Entity Address, Address Line One	1000 Louisiana Street, Suite 3300
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77002
City Area Code	713
Local Phone Number	574-1880
Title of 12(b) Security	Common Stock, $0.0001 par value
Trading Symbol	NEXT
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		257,994,156
Entity Central Index Key	0001612720
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2024
Amendment Flag	true
Amendment Description	Explanatory NoteThe purpose of the filing of this Form 10-Q/A is to correct certain line items in the Company’s Consolidated Financial Statements for the three months ended March 31, 2024 that were originally reported incorrectly due to a clerical error. The following line items within the Statement of Cash Flows for the three months ended March 31, 2024 are changed as follows (in thousands): acquisition of property, plant and equipment has been changed from $(790,332) to $(774,615); net cash used in investing activities has been changed from $(796,365) to $(780,648); debt and equity issuance costs has been changed from $(4,309) to $(20,026); and net cash provided by financing activities has been changed from $782,110 to $766,393. Within the table of Debt Maturities in Note 6 to the Consolidated Financial Statements, the “2026” row has been changed from $35,619 to $26,881 and the “Thereafter” row has been changed from $2,407,262 to $2,416,000. There was an additional deletion of the line item for cash paid for interest, net of amounts capitalized in Note 13 to the Consolidated Financial Statements and corresponding changes to the disclosure of net cash used in investing activities and net cash provided by financial activities within Management’s Discussion and Analysis of Financial Condition and Results of Operations under the subheadings “Liquidity and Capital Resources—Investing Cash Flows” and “—Financing Cash Flows.”No other changes have been made to the Form 10-Q. This Form 10-Q/A speaks as of the original filing date and time of the Form 10-Q, and does not modify or update any other disclosures made in the Form 10-Q.