Commitments and Contingencies - Summary of Commitments (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($)
Commitments and Contingencies
Investment Commitment	$ 158,537
2017 Funding	22,992
Commitments funded	66,580
Remaining commitment	91,957
Real estate properties
Commitments and Contingencies
Investment Commitment	60,274
2017 Funding	12,120
Commitments funded	28,456
Remaining commitment	31,818
Accrued incentives and earn-out liabilities
Commitments and Contingencies
Investment Commitment	14,000
Remaining commitment	14,000
Lease incentives
Commitments and Contingencies
Investment Commitment	7,113
2017 Funding	438
Commitments funded	438
Remaining commitment	6,675
Mortgage loans
Commitments and Contingencies
Investment Commitment	51,000
2017 Funding	9,333
Commitments funded	14,672
Remaining commitment	36,328
Joint venture investments
Commitments and Contingencies
Investment Commitment	25,650
2017 Funding	1,101
Commitments funded	23,014
Remaining commitment	2,636
Notes receivable
Commitments and Contingencies
Investment Commitment	500
Remaining commitment	$ 500