2016 Management Internalization - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Dec. 20, 2016	Dec. 31, 2016	Dec. 31, 2017
Business Acquisition [Line Items]
Net assets acquired			$ 86,723
Management internalization expense	$ 2,119	$ 44,976
Management Internalization
Business Acquisition [Line Items]
Present value of unfavorable difference between actual and potential payment based on agreements.	43,000
Net assets acquired	143
Consideration transferred	43,000
Business acquisition loss recognized amount	$ 42,857