Commitments and Contingencies (Details) $ in Thousands	Dec. 31, 2016 USD ($) loan
Commitments and Contingencies.
Number of loans with future funding commitments | loan	47
Value of loans with future funding commitments	$ 1,400,000
Value of loans with future funding commitments expected to fund	1,100,000
Corporate Rents
2017	6,318
2018	6,241
2019	5,930
2020	5,305
2021	2,647
Total	26,441
Sublease Income
2017	1,782
2018	1,685
2019	1,171
2020	1,004
2021	677
Total	6,319
Investment Property Ground Leases
2017	115
2018	116
2019	117
2020	119
2021	121
Thereafter	6,151
Total	$ 6,739