Acquisitions of Real Estate - Consideration for the Sacramento Facility and the Adjusted Preliminary Allocation of the Fair Value of Assets Acquired (Detail) (QualityTech, LP [Member], USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013
Loans At Acquisition Date [Line Items]
Working capital
Buildings	52,439
Land	1,481
Total purchase price	63,250
Buildings	40 years
Original Sacramento Facility [Member]
Loans At Acquisition Date [Line Items]
Working capital
Buildings	52,753
Land	1,485
Total purchase price	63,250
Adjustment [Member]
Loans At Acquisition Date [Line Items]
Working capital
Buildings	(314)
Land	(4)
Total purchase price
Tenant Relationship [Member]
Loans At Acquisition Date [Line Items]
Above (below) market leases	5,366
Above (below) market leases	4 years
Tenant Relationship [Member] | Original Sacramento Facility [Member]
Loans At Acquisition Date [Line Items]
Above (below) market leases	5,029
Tenant Relationship [Member] | Adjustment [Member]
Loans At Acquisition Date [Line Items]
Above (below) market leases	337
In Place Leases [Member]
Loans At Acquisition Date [Line Items]
Above (below) market leases	3,964
Above (below) market leases	2 years
In Place Leases [Member] | Original Sacramento Facility [Member]
Loans At Acquisition Date [Line Items]
Above (below) market leases	3,202
In Place Leases [Member] | Adjustment [Member]
Loans At Acquisition Date [Line Items]
Above (below) market leases	762
Above (Below) Market Leases [Member]
Loans At Acquisition Date [Line Items]
Above (below) market leases
Above (below) market leases	1 year
Above (Below) Market Leases [Member] | Original Sacramento Facility [Member]
Loans At Acquisition Date [Line Items]
Above (below) market leases	781
Above (Below) Market Leases [Member] | Adjustment [Member]
Loans At Acquisition Date [Line Items]
Above (below) market leases	$ (781)