Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
OPERATING ACTIVITIES
Net income	$ 4,865	$ 2,871
Results from discontinued operations		(107)
Income from continuing operations	4,865	2,764
Adjustments to reconcile income from continuing operations to net cash provided by operating activities:
Deferred rent revenue and amortization of lease intangibles	(1,163)	(1,551)
Depreciation and amortization	17,013	14,854
Amortization of debt issuance costs and debt fair value adjustments	983	962
Stock-based compensation expense	676	699
Loss from real estate joint ventures	54
Other, net	(1,256)	416
Changes in operating assets and liabilities
Change in restricted cash	(500)	(595)
Change in accounts receivable	(1,198)	1,513
Change in other assets	(216)	(1,304)
Change in accounts payable and accrued expenses	5,956	408
Change in security deposits payable	211	(85)
Change in other liabilities and deferred credits	247	(209)
Net cash provided by operating activities of continuing operations	25,672	17,872
Net cash provided by operating activities of discontinued operations		628
Net cash provided by operating activities	25,672	18,500
INVESTING ACTIVITIES
Acquisition of real estate, net of cash acquired		(32,918)
Capital expenditures	(9,902)	(5,990)
Change in restricted cash	518	(139)
Leasing commissions	(338)	(467)
Maturity of marketable securities		1,613
Net cash used in investing activities of continuing operations	(9,722)	(37,901)
Net cash used in investing activities of discontinued operations		(11)
Net cash used in investing activities	(9,722)	(37,912)
FINANCING ACTIVITIES
Change in restricted cash	(1,400)
Issuance of secured notes payable		21,900
Repayment of secured notes payable	(943)	(1,161)
Debt issuance costs		(924)
Dividends paid to common stock and unitholders	(12,114)	(12,113)
Deferred offering costs		(361)
Net cash (used in) provided by financing activities	(14,457)	7,341
Net increase (decrease) in cash and cash equivalents	1,493	(12,071)
Cash and cash equivalents, beginning of period	42,479	112,723
Cash and cash equivalents, end of period	$ 43,972	$ 100,652