Income Taxes - Deferred Income Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Gross deferred income tax assets:
NOL carryforwards	$ 297,900	$ 287,516
Basis difference – real estate properties	59,259	42,472
Basis difference – equity investments	0	445
Section 163(j) interest limitation	1,486	480
Capital loss carryforward	16,845	1
Other – temporary differences	4,122	2,754
Total gross deferred income tax assets	379,612	333,668
Valuation allowance	(326,706)	(299,092)
Gross deferred income tax assets, net of valuation allowance	52,906	34,576
Gross deferred income tax liabilities:
Basis difference – real estate properties	79,230	78,113
Basis difference – equity investments	31,995	12,622
Other – temporary differences	999	1,898
Total gross deferred income tax liabilities	112,224	92,633
Net deferred income tax liabilities	$ 59,318	$ 58,057