Fair Value of Assets and Liabilities - Recurring and Nonrecurring Assets (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($) property	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)
Fair Value of Assets and Liabilities
Loss on impairment of real estate assets	$ 8,521	$ 0	$ 14,105	$ 5,800
Nonrecurring
Fair Value of Assets and Liabilities
Other liability	89,050		89,050
Nonrecurring | Level 1 inputs
Fair Value of Assets and Liabilities
Other liability	0		0
Nonrecurring | Level 2 inputs
Fair Value of Assets and Liabilities
Other liability	89,050		89,050
Nonrecurring | Level 3 inputs
Fair Value of Assets and Liabilities
Other liability	0		$ 0
Held-for-sale
Fair Value of Assets and Liabilities
Loss on impairment of real estate assets	$ 6,342
Number of impaired properties | property	8