Impairment Provisions (Summary of Impairment Provisions) (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment provision on properties	$ 9,669		$ 4,688		$ 37,411
Provision for impairment	9,669		1,387		16,917
Land held for development or available for sale
Impaired Long-Lived Assets Held and Used [Line Items]
Provision for impairment	327	[1]	1,387	[1]	11,468	[1]
Land held for development or available for sale | Changes to estimated sales price assumptions and additional costs to complete to ready parcels for sale
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment provision on properties	300
Wholly-owned income producing properties
Impaired Long-Lived Assets Held and Used [Line Items]
Provision for impairment	$ 9,400

[1] In 2013, changes to estimated sales price assumptions triggered an impairment provision of $0.3 million. Refer to Note 1 under Accounting for the Impairment of Long-Lived Assets for a discussion of inputs used in determining the fair value of long-lived assets.