Loan Participations Sold (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) loan	Dec. 31, 2018 USD ($) loan	Dec. 31, 2017 USD ($)	Nov. 30, 2019 USD ($)	Oct. 31, 2019 USD ($)	May 31, 2019 USD ($)
Participating Mortgage Loans [Line Items]
Mortgage loan syndicated	$ 64,966				$ 85,465				$ 64,966	$ 85,465
Interest income	31,084	$ 28,627	$ 25,855	$ 29,909	27,431	$ 28,558	$ 21,565	$ 21,004	$ 115,475	$ 98,558	$ 61,921
Total loan
Participating Mortgage Loans [Line Items]
Number of loans sold | loan									1	1
Principal Balance	328,500				99,757				$ 328,500	$ 99,757			$ 328,500	$ 286,200
Mortgage loan syndicated	$ 326,881				$ 99,368				$ 326,881	$ 99,368
Yield/cost	2.50%				3.00%				2.50%	3.00%
Pari Passu Loan Syndication
Participating Mortgage Loans [Line Items]
Number of loans sold | loan									1
Principal Balance	$ 65,000								$ 65,000
Mortgage loan syndicated	$ 64,966								$ 64,966			$ 65,000	$ 65,000	$ 65,000
Yield/cost	2.50%								2.50%
Senior Participation Loan
Participating Mortgage Loans [Line Items]
Number of loans sold | loan										1
Principal Balance					$ 85,880					$ 85,880
Mortgage loan syndicated					$ 85,465					$ 85,465
Yield/cost					1.80%					1.80%
Partial recourse, amount					$ 10,000					$ 10,000
Loan participations
Participating Mortgage Loans [Line Items]
Interest income									$ 2,800	3,300
Interest expense									$ 2,800	$ 3,300