Investment in Real Estate Properties - Summary of Rental Revenue and Depreciation and Amortization Expense (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Increase (Decrease) to Rental Revenue:
Straight-line rent adjustments	$ 3,197	$ 5,377	$ 12,247	$ 11,307
Above-market lease amortization	(1,885)	(2,004)	(6,945)	(5,450)
Below-market lease amortization	1,428	1,134	4,413	2,705
Real Estate-Related Depreciation and Amortization:
Depreciation expense	19,095	15,276	56,674	38,889
Intangible lease asset amortization	$ 14,773	$ 15,749	$ 50,054	$ 46,020