Income Taxes - Summary of Deferred Tax Assets and Liabilities (Detail) - TRS [Member] - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Income Tax Expense Benefit [Line Items]
Deferred tax assets	$ 61,742	$ 65,891
Deferred tax liabilities	(404)	(514)
Valuation allowance	(61,338)	(65,377)
Net deferred tax asset	$ 0	$ 0