Debt - Schedule of Long-Term Debt (Parenthetical) (Detail)	9 Months Ended
	Sep. 30, 2018 Extension
LIBOR [Member]
Debt Instrument [Line Items]
Debt, base interest rate	2.26%
Revolving Facility [Member]
Debt Instrument [Line Items]
Extension period	1 year
CMBS Facility [Member]
Debt Instrument [Line Items]
Number of extension options	5
Extension option period	12 months