Allocation of Purchase Price to Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Intangible assets		$ 6,500
Liabilities (real property and operating)		(2,300)
Net cash paid		7,000
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 in 2014	(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 in 2014		(150)
Net cash paid		$ 15,600
2013 Acquisitions
Business Acquisition [Line Items]
Land			$ 316
Buildings and improvements			3,749
Intangible assets			610
Other assets			21
Liabilities (real property and operating)			(11)
Net cash paid			$ 4,685