Real Estate and Accumulated Depreciation - Schedule III (Changes in Real Estate Properties and Accumulated Depreciation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Real estate investments, at cost:
Balance at beginning of year	$ 3,070,852	$ 3,056,695	$ 1,724,258
Additions - acquisitions	365,159	201,896	1,490,332
Additions - improvements	14,006	13,189	0
Disposals	(80,631)	(146,109)	(131,185)
Impairment charges	(699)	(9,363)	(20,580)
Reclassified to assets held for sale	(1,313)	(45,456)	(6,130)
Balance at end of the year	3,367,374	3,070,852	3,056,695
Accumulated depreciation:
Balance at beginning of year	311,214	256,771	183,437
Depreciation expense	78,395	84,482	85,175
Disposals	(20,022)	(25,131)	(10,415)
Reclassified to assets held for sale	(137)	(4,908)	(1,426)
Balance at end of the year	$ 369,450	$ 311,214	$ 256,771