Real Estate Assets Contributions to revenue and net income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Combination, Separately Recognized Transactions [Line Items]
Revenues	$ 124,866	$ 120,203	$ 113,852	$ 111,506	$ 106,280	$ 104,232	$ 96,389	$ 90,370	$ 470,427	$ 397,271	$ 294,005
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ (1,364)	$ (2,137)	$ (1,677)	$ (2,280)	$ 27,199	$ 8,354	$ (5,278)	$ 14,263	$ (7,458)	$ 44,538	$ 28,667