Supplemental Information to Statements of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Interest Expense Capitalized in Connection with Development Activity	$ 3,077	$ 1,185
Mortgage Loan Payable Assumed in Conjunction with a Property Acquisition	0	12,026
Write-off of Fully Depreciated Assets	(44,234)	(36,560)
Supplemental Schedule of Non-Cash Investing and Financing Activities:
Distribution Payable	9,788
Exchange of Operating Partnership Units for Common Stock:
Conversion of Units to Common Stock	0	0
Noncontrolling Interest
Exchange of Operating Partnership Units for Common Stock:
Conversion of Units to Common Stock	(943)	(2,710)
Common Stock
Exchange of Operating Partnership Units for Common Stock:
Conversion of Units to Common Stock	1	3
Additional Paid-in Capital
Exchange of Operating Partnership Units for Common Stock:
Conversion of Units to Common Stock	942	2,707
Common Stock
Supplemental Schedule of Non-Cash Investing and Financing Activities:
Distribution Payable	9,788	0
Preferred Stock
Supplemental Schedule of Non-Cash Investing and Financing Activities:
Distribution Payable	$ 0	$ 5,177