Summary of Activity in Real Estate Facilities (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Real estate facilities
Balance at beginning of year	$ 604,727,895		$ 510,395,576
Facility acquisitions	74,743,745		85,722,709
Land disposition			(1,675,860)
Impact of foreign exchange rate changes	(2,415,103)		614,721	(695,064)
Improvements and additions	17,082,250		9,670,749
Balance at end of year	694,138,787	[1]	604,727,895	510,395,576
Accumulated depreciation
Beginning balance	(29,840,320)		(15,971,288)
Depreciation expense	(16,591,835)		(13,869,032)
Ending balance	$ (46,432,155)		$ (29,840,320)	$ (15,971,288)

[1] The aggregate cost of real estate for United States federal income tax purposes is $761,130,955.