Income Taxes - Summary of Combined Activity and Taxable Activity (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
TRS [Member]
Income Before Income Taxes [Line Items]
Book income (loss) before income taxes	$ 9,953	$ (1,446)	$ 12,104
Total expense	17	0	0
Puerto Rico [Member]
Income Before Income Taxes [Line Items]
Book income (loss) before income taxes	0	0	(11,040)
Total expense	0	0	0
Puerto Rico [Member] | TRS [Member]
Income Before Income Taxes [Line Items]
Current	17	0	0
Deferred	$ 0	$ 0	$ 0