Stockholders' Equity - Tax Composition of Distributions Declared (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Equity [Abstract]
Taxable as ordinary income	1.20%	28.00%	0.00%
Taxable as qualified dividends	0.20%	0.00%	0.00%
Taxable as capital gain	0.00%	18.30%	0.00%
Return of capital	98.60%	53.70%	100.00%