Mortgage Notes Payable, Credit Facilities and Senior Notes - Combined Aggregate Principal Maturities of Mortgage Notes Payable (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Total
Total mortgage notes payable	$ 88,511	$ 107,915
Mortgage Notes Payable
Principal Repayments
2019	0
2020	0
2021	0
2022	23,129
2023	0
Thereafter	58,787
Long-term Debt	81,916
Scheduled Amortization
2019	551
2020	577
2021	717
2022	1,003
2023	686
Thereafter	1,258
Total	4,792
Mortgage Premium
2019	481
2020	481
2021	481
2022	344
2023	216
Thereafter	71
Total	2,074
Total
2019	1,032
2020	1,058
2021	1,198
2022	24,476
2023	902
Thereafter	60,116
Total mortgage notes payable	$ 88,782