Subsequent Events - Additional Information (Details)			1 Months Ended	9 Months Ended
	Oct. 25, 2018 USD ($) $ / shares	Jul. 03, 2017	Nov. 05, 2018 USD ($) Loan	Sep. 30, 2018 USD ($)		Sep. 18, 2018 USD ($) $ / shares	Dec. 31, 2017 USD ($)		Sep. 30, 2017 USD ($)	Sep. 26, 2017 $ / shares
Subsequent Event [Line Items]
Principal amount of notes issued				$ 3,610,303,000			$ 3,376,158,000
Dividend payable date		Jul. 25, 2017		Jul. 03, 2017
Dividends Payable				$ 28,918,000	[1]	$ 28,900,000	$ 23,068,000	[1]	$ 20,135,000
Common Stock
Subsequent Event [Line Items]
Dividend amount per share | $ / shares						$ 0.43				$ 0.33
Subsequent Events
Subsequent Event [Line Items]
Number of first mortgage loans closed | Loan			4
Principal amount of notes issued			$ 540,000,000
Subsequent Events | Common Stock
Subsequent Event [Line Items]
Dividend payable date	Oct. 25, 2018
Dividend amount per share | $ / shares	$ 0.43
Dividends Payable	$ 28,900,000

[1] At December 31, 2017, there were no VIE assets or liabilities recorded in the Company’s Total Assets and Total Liabilities. The Company’s consolidated Total Assets and Total Liabilities at September 30, 2018 include VIE assets and liabilities of $954.4 million and $741.5 million, respectively. These assets can be used only to satisfy obligations of the VIE, and creditors of the VIE have recourse only to these assets, and not to TPG RE Finance Trust, Inc. See Note 5 to the Consolidated Financial Statements for details