CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 54,620	$ 49,960	$ 45,997
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	34,694	32,348	26,886
Net amortization of debt premium and deferred financing fees	1,340	1,332	1,045
Straight line rental income	(3,067)	(3,553)	(1,729)
Amortization of acquired real estate leases	21,608	19,507	13,071
Amortization of deferred leasing costs	1,599	1,122	630
Other non-cash expenses	1,268	1,598	763
Loss on asset impairment	10,142	494
Net gain on sale of properties	(8,168)
Equity in earnings of an investee	(334)	(316)	(139)
Change in assets and liabilities:
Restricted cash	(136)	183	(188)
Deferred leasing costs	(4,279)	(5,183)	(2,702)
Rents receivable	(1,565)	3,454	(8,071)
Other assets	(1,063)	257	(1,708)
Accounts payable and accrued expenses	2,492	(940)	3,909
Due to related persons	(760)	45	2,723
Cash provided by operating activities	108,391	100,308	80,487
CASH FLOWS FROM INVESTING ACTIVITIES:
Real estate acquisitions and deposits	(112,574)	(213,626)	(387,491)
Real estate improvements	(23,252)	(18,841)	(3,060)
Proceeds from sale of properties, net	18,319
Cash used in investing activities	(117,507)	(232,467)	(390,551)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common shares, net		166,718	157,870
Repayment of mortgage notes payable	(1,933)	(1,793)	(1,005)
Borrowings on unsecured revolving credit facility	216,500	230,500	472,500
Repayments on unsecured revolving credit facility	(109,000)	(526,500)	(245,000)
Proceeds from unsecured term loan		350,000
Financing fees		(1,964)	(3,074)
Distributions to common shareholders	(94,043)	(82,819)	(70,392)
Cash provided by financing activities	11,524	134,142	310,899
Increase in cash and cash equivalents	2,408	1,983	835
Cash and cash equivalents at beginning of year	5,255	3,272	2,437
Cash and cash equivalents at end of year	7,663	5,255	3,272
Supplemental cash flow information
Interest paid	15,336	15,469	10,309
Income taxes paid	169	117	72
Non-cash investing activities
Real estate acquisitions funded with the assumption of mortgage debt			(49,395)
Non-cash financing activities
Assumption of mortgage debt			49,395
Issuance of common shares	$ 1,697	$ 1,902	$ 721