Commitments and Contingencies - Future Minimum Rental Payments (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
2017 (remaining)	$ 443,000		$ 443,000
2018	1,767,000		1,767,000
2019	1,767,000		1,767,000
2020	1,767,000		1,767,000
2021	1,767,000		1,767,000
2022 and thereafter	34,905,000		34,905,000
Total	42,416,000		42,416,000
Other Expenses [Abstract]
Operating ground lease expense	$ 313,000	$ 241,000	$ 936,000	$ 734,000