Debt Five Year Maturity Schedule (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
2018	$ 2,366
2019	2,456
2020	65,751
2021	200,000
2022	110,000
Thereafter	510,000
Total debt principal payments	890,573
Mortgage loan premiums and deferred financing costs	(5,336)
Total debt	$ 885,237	$ 996,251