Commitments and Contingencies - Contractual Obligations (Details) - USD ($) $ in Thousands		Jun. 30, 2021	Dec. 31, 2020
Other Commitments [Line Items]
Less than 1 year		$ 293,713
1-3 years		121,816
3-5 years		2,048
More than 5 years		6,501
Total		424,078
Construction holdbacks
Other Commitments [Line Items]
Less than 1 year	[1]	292,787
1-3 years	[1]	119,964
3-5 years	[1]	0
More than 5 years	[1]	0
Total	[1]	412,751
Operating lease obligations
Other Commitments [Line Items]
Less than 1 year		926
1-3 years		1,852
3-5 years		2,048
More than 5 years		6,501
Total		11,327
Broadmark Private REIT, LLC
Other Commitments [Line Items]
Construction holdbacks		$ 34,700	$ 40,400

[1] Includes construction holdbacks of $34.7 million on participating interests sold to the Private REIT as of June 30, 2021. The funding timing and amounts of construction holdbacks are uncertain as these commitments relate to loans for construction costs and depend on the progress and performance of the underlying projects.