Dispositions, Real Property Held for Sale and Impairment - Dispositions and Assets Held for Sale (Details) - Disposal group, disposed of by sale, not discontinued operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues:
Total revenues	$ 7,103	$ 7,471	$ 58,302	$ 262,951
Expenses:
Interest expense	32	1,737	1,471	10,039
Property operating expenses	925	33,330	7,942	150,501
Provision for depreciation	440	18,085	8,665	72,877
Total expenses	1,397	53,152	18,078	233,417
Income (loss) from real estate dispositions, net	$ 5,706	$ (45,681)	$ 40,224	$ 29,534