Supplemental Information to Statements of Cash Flows - Cash Flow Information (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Supplemental Cash Flow Information [Line Items]
Interest Expense Capitalized in Connection with Development Activity	$ 742	$ 1,998
Supplemental Schedule of Non-Cash Investing and Financing Activities:
Dividend Payable	11,891
Exchange of Operating Partnership Units for Common Stock:
Conversion of Units to Common Stock	0	0
Assumption of Liabilities in Connection with the Acquisition of Real Estate	183	298
Accounts Payable Related to Construction in Progress and Additions to Investment in Real Estate	17,829	13,836
Write-off of Fully Depreciated Assets	(19,462)	(36,010)
Noncontrolling Interest
Exchange of Operating Partnership Units for Common Stock:
Conversion of Units to Common Stock	(1,333)	(804)
Common Stock
Exchange of Operating Partnership Units for Common Stock:
Conversion of Units to Common Stock	1	1
Additional Paid-in Capital
Exchange of Operating Partnership Units for Common Stock:
Conversion of Units to Common Stock	1,332	803
Common Stock and Operating Partnership Units [Member]
Supplemental Schedule of Non-Cash Investing and Financing Activities:
Dividend Payable	11,891	9,745
Preferred Stock
Supplemental Schedule of Non-Cash Investing and Financing Activities:
Dividend Payable	$ 0	$ 2,056