Held for Sale (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Balance Sheet data (as of the period ended):
Land	$ 289,751	$ 230,206
Buildings, improvements and lease intangibles	3,986,326	3,675,415
Total real estate properties	4,359,993	3,974,071
Less accumulated depreciation	(1,121,102)	(1,015,174)
Total real estate properties, net	3,238,891	2,958,897
Assets held for sale, net	37	9,272
Liabilities of properties held for sale	145	587
Discontinued Operations [Member]
Balance Sheet data (as of the period ended):
Total real estate properties	0	19,356
Total real estate properties, net	0	8,699
Assets held for sale, net	37	9,272
Liabilities of properties held for sale	145	587
Disposal Group, Held-for-sale, Not Discontinued Operations [Member]
Balance Sheet data (as of the period ended):
Land	0	1,125
Buildings, improvements and lease intangibles		18,231
Less accumulated depreciation	0	(10,657)
Other assets, net	37	573
Accounts payable and accrued liabilities	37	450
Other liabilities	$ 108	$ 137