Fair Value - Nonrecurring Fair Value (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Operating real estate, net	$ 1,571,696		$ 1,700,218
Assets held for sale	0		1,649
Impairment loss	91,400	$ 10,100
Nonrecurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Operating real estate, net	109,262		27,450
Assets held for sale	927		1,649
Nonrecurring | Level 3 | Operating Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment loss	90,715		27,021
Nonrecurring | Level 3 | Assets Held-For-Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment loss	$ 722		$ 533