Commitments and Contingencies - Additional Information (Detail) (USD $)	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Ground Lease Commitments, 2013	$ 49,680,000
Ground Lease Commitments, 2014	46,993,000
Ground Lease Commitments, 2015	42,425,000
Ground Lease Commitments, 2016	39,740,000
Ground Lease Commitments, 2017	33,099,000
Ground Lease Commitments, Thereafter	127,496,000
Ground Lease [Member]
Property, Plant and Equipment [Line Items]
Future funding commitments	71,092,000
Ground Lease Commitments, 2013	1,405,000
Ground Lease Commitments, 2014	1,463,000
Ground Lease Commitments, 2015	1,592,000
Ground Lease Commitments, 2016	1,656,000
Ground Lease Commitments, 2017	1,791,000
Ground Lease Commitments, Thereafter	$ 107,627,000