Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Significant Accounting Policies [Line Items]
Intangible assets and goodwill	$ 12,100		$ 12,100		$ 12,100
Intangible assets	4,300		4,300		4,300
Goodwill	7,800		7,800		7,800
Accumulated amortization of identified intangible assets	2,400		2,400		2,200
Amortization of in-place leases	669	$ 1,401	1,334	$ 2,716
Cash and cash equivalents, restricted cash	5,000		5,000		5,000
Debt, secured and unsecured	2,200,000		2,200,000		2,200,000
Accumulated amortization for deferred financing costs	31,800		31,800		29,800
Fair Value, Inputs, Level 2
Significant Accounting Policies [Line Items]
Mortgage notes payable fair value	2,200,000		2,200,000		$ 2,300,000
Identified Intangible Assets
Significant Accounting Policies [Line Items]
Amortization of in-place leases	$ 100	$ 100	$ 100	$ 100