Dispositions and Assets Held for Sale - Dispositions and Assets Held for Sale (Details) - Disposal Group, Disposed of by Sale, Not Discontinued Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues:
Total revenues	$ 112,694	$ 121,079	$ 228,441	$ 249,639
Expenses:
Interest expense	479	579	983	1,200
Property operating expenses	70,244	74,213	146,260	150,120
Provision for depreciation	12,520	18,431	24,897	38,275
Total expenses	83,243	93,223	172,140	189,595
Income (loss) from real estate dispositions, net	$ 29,451	$ 27,856	$ 56,301	$ 60,044