Supplemental Information to Statements of Cash Flows - Cash Flow Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Supplemental Cash Flow Information [Line Items]
Interest Expense Capitalized in Connection with Development Activity	$ 380	$ 930
Supplemental Schedule of Non-Cash Investing and Financing Activities:
Dividend Payable	11,921
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	138	0
Accounts Payable Related to Construction in Progress and Additions to Investment in Real Estate	12,650	13,444
Write-off of Fully Depreciated Assets	(9,863)	(13,890)
Noncontrolling Interest
Exchange of Operating Partnership Units for Common Stock:
Conversion of Units to Common Stock	(1,279)	0
Common Stock
Exchange of Operating Partnership Units for Common Stock:
Conversion of Units to Common Stock	1	0
Additional Paid-in Capital
Exchange of Operating Partnership Units for Common Stock:
Conversion of Units to Common Stock	1,278	0
Common Stock and Operating Partnership Units [Member]
Supplemental Schedule of Non-Cash Investing and Financing Activities:
Dividend Payable	11,921	9,536
Preferred Stock
Supplemental Schedule of Non-Cash Investing and Financing Activities:
Dividend Payable	$ 0	$ 4,289