Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended					12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2018
Noncash activities
Capital contribution to fund general and administrative expense reimbursement	$ 994				$ 1,202
Issuance of common units for assets acquired from Fund H						$ 7,700
Distributions payable to preferred unitholders	1,685				1,244
Offering costs included in accounts payable and accrued liabilities					207
Deferred loan costs included in accounts payable and accrued liabilities					44
Initial recognition of lease liabilities related to right of use assets	7,589
Purchase price for acquisitions and construction activities included in accounts payable					9,677
Cash flows related to interest paid
Cash paid for interest	3,049				5,438
Capitalized interest	308				76
Income taxes paid	126
Preferred Units Series C
Noncash activities
Accretion of Series C preferred units	$ 356
Unit Exchange Acquisitions
Noncash activities
Issuance of common units for assets acquired from Fund H		$ 900	$ 1,800	$ 1,800	3,200
Unit Exchange Program acquisitions					3,147
Landmark, General Partner and affiliates
Noncash activities
Purchase price for acquisitions included in due to Landmark and affiliates					493
Landmark Dividend Growth Fund H LLC
Noncash activities
Issuance of common units for assets acquired from Fund H					$ 27,342