Allocation of Purchase Price to Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Aug. 31, 2014
Business Acquisition [Line Items]
Intangible assets			$ 6,500
Debt (including fair value adjustment of $362)			(29,800)
Net cash paid				$ 7,000
2016 Acquisitions
Business Acquisition [Line Items]
Land	$ 9,914
Buildings and improvements	50,117
Intangible assets	9,211
Below-market lease intangibles	(1,287)
Deposit paid	(150)
Debt (including fair value adjustment of $362)	(7,499)
Financing fees paid on debt acquired	83
Net cash paid	$ 60,389
2015 Acquisitions
Business Acquisition [Line Items]
Land		$ 7,050
Buildings and improvements		17,518
Intangible assets		2,182
Cash received- exchange transaction		2,000
Other liabilities		(116)
Deposit paid		(100)
Net book value of property divested in exchange transaction		(3,027)
Gain on exchange transaction		(8,742)
Net cash paid		$ 16,765
2014 Acquisitions
Business Acquisition [Line Items]
Land			3,010
Buildings and improvements			10,664
Intangible assets			2,076
Deposit paid			(150)
Net cash paid			$ 15,600