Schedule III - Real Estate Investments - Summary of Historical Cost and Accumulated Depreciation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property
Balance, beginning of period	$ 2,812,856	$ 2,357,322	$ 1,964,857
Disposals	(41,363)	(43,616)	(18,198)
Additions (acquisitions and improvements)	458,935	499,150	410,663
Balance, end of period	3,230,428	2,812,856	2,357,322
Accumulated depreciation
Balance, beginning of period	(467,644)	(394,823)	(317,834)
Disposals	28,172	30,139	13,970
Additions (depreciation and amortization expense)	(119,088)	(102,960)	(90,959)
Balance, end of period	$ (558,560)	$ (467,644)	$ (394,823)