Organization (Details) $ / shares in Units, $ in Thousands		12 Months Ended
	Sep. 30, 2021 USD ($) loan $ / shares shares	Dec. 31, 2021 $ / shares shares	Dec. 31, 2020 $ / shares
Subsidiary, Sale of Stock [Line Items]
Common shares, par value (in dollars per share) | $ / shares		$ 0.001	$ 0.001
TRMT Merger
Subsidiary, Sale of Stock [Line Items]
Common shares, par value (in dollars per share) | $ / shares	$ 0.001
Exchange ratio of shares issued per acquiree share ( in shares) | shares	0.516	0.516
Share price (in dollars per share) | $ / shares	$ 10.31
Consideration transferred and liabilities assumed	$ 169,150
Assumed Citibank Master Repurchase Facility, principal balance	128,962
Merger related costs	6,160
Assumed working capital	$ 10,146
Number of loans acquired | loan	10
Aggregate principle loan balance acquired	$ 204,692
TRMT Merger | Tremont Mortgage Trust
Subsidiary, Sale of Stock [Line Items]
Common shares, par value (in dollars per share) | $ / shares	$ 0.01
TRMT Merger | Tremont Mortgage Trust And Seven Hills Realty Trust
Subsidiary, Sale of Stock [Line Items]
Merger related costs	$ 6,160