Schedule of Other Assets (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Other Assets [Line Items]
Debt issuance costs, accumulated amortization	$ 2,711	$ 1,633
Intangible lease value
Schedule of Other Assets [Line Items]
Intangible assets, accumulated amortization	6,920	4,990
Other intangible assets
Schedule of Other Assets [Line Items]
Intangible assets, accumulated amortization	$ 2,625	$ 1,421