Ground Leases - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Operating Leases [Line Items]
Description of Lessor Leasing Arrangements, Operating Leases	The majority of the lease terms require twelve equal payments per year plus additional rents calculated as a percentage of gross revenues. Future minimum rental payments exclude payments related to the Colony Cove Property lease as we have provided required notification of our intent to exercise the purchase option for the land which is expected to close in early 2014.
Operating Lease, rent revenue	$ 3.4	$ 3.3	$ 2.5
Operating Lease terms	The leases entered into between the customer and us for the rental of a Site are generally month-to-month or for a period of one to ten years, renewable upon the consent of the parties or, in some instances, as provided by statute.
Minimum
Schedule of Operating Leases [Line Items]
Ground leases, expiration period year	2015
Maximum
Schedule of Operating Leases [Line Items]
Ground leases, expiration period year	2054