Schedule III - Reconciliation of Real Estate Assets and Accumulated Depreciation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Real Estate
Balance at beginning of period	$ 200,675	$ 377,446	$ 587,952
Additions during the period:
Improvements, etc.	(313)	3,301	3,632
Consolidation of property		15,082
Deductions during this period:
Cost of real estate sold	(144,923)	(138,656)	(82,793)
Asset impairments	(2,861)	(3,908)
Deconsolidation of property			(118,765)
Liquidation adjustment	(12,442)	(52,590)	(12,580)
Balance at end of period	40,136	200,675	377,446
Accumulated Depreciation
Balance at beginning of period	14,023	23,584	30,627
Disposal of properties	(6,863)	(9,561)	(2,227)
Deconsolidation of property			(4,816)
Balance at end of period	$ 7,160	$ 14,023	$ 23,584