Summary of Repurchase Agreements Secured by Commercial Mortgage Loans, CMBS, CRE CLO Investments, Long - term Borrowings, and Counterparty Concentration (Parenthetical) (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2019	Dec. 31, 2018
Repurchase Agreement Counterparty [Line Items]
Interest receivable	[1]	$ 24,470	$ 20,731
Accrued Interest Payable	[1]	7,964	6,146
Unamortized deferred financing fees			6,700
Commercial Mortgage Loans
Repurchase Agreement Counterparty [Line Items]
Interest receivable		12,800	14,500
Premium, discount and origination fees		15,800	17,300
Accrued Interest Payable		2,900	3,100
Unamortized deferred financing fees		6,200
CMBS and CRE CLO Investments
Repurchase Agreement Counterparty [Line Items]
Interest receivable		1,000	100
Premium, discount and origination fees		1,600	2,200
Accrued Interest Payable		$ 800	$ 300

[1] The Company’s consolidated Total Assets and Total Liabilities at March 31, 2019 include assets and liabilities of variable interest entities (“VIEs”) of $1.7 billion and $1.3 billion, respectively. The Company’s consolidated Total Assets and Total Liabilities at December 31, 2018 include assets and liabilities of VIEs of $1.9 billion and $1.5 billion, respectively. These assets can be used only to satisfy obligations of the VIEs, and creditors of the VIEs have recourse only to these assets, and not to TPG RE Finance Trust, Inc. See Note 5 to the Consolidated Financial Statements for details