Schedule III Real Estate and Accumulated Depreciation - Changes in Total Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cost
Balance at beginning of period	$ 563,728	$ 494,874	$ 504,853
Acquisitions	23,377	55,250
Capitalized costs	4,563	1,104	21
Conversion of mortgage note	6,384	12,500
Elimination of earn-out payment			(10,000)
Balance at end of period	598,052	563,728	494,874
Accumulated Depreciation
Balance at beginning of period	41,984	26,052	11,172
Depreciation	17,627	15,932	14,880
Balance at end of period	$ 59,611	$ 41,984	$ 26,052