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 (loss)	$ 31,612	$ 10,716	$ (10,779)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	65,785	64,327	68,967
Amortization of above/below market leases	(823)	(1,505)	(1,650)
Amortization of deferred financing costs	1,739	1,681	1,556
Gain on early extinguishment of debt			(939)
Share-based compensation	6,770	5,650	2,958
Amortization of discount to fair market value of acquired loan			687
Bad debt expense	244	544	292
Changes in operating assets and liabilities:
Accounts receivable	(682)	(3,657)	(1,523)
Due to and due from related parties			2
Deferred rent receivable	(2,248)	(3,966)	(4,986)
Deferred leasing costs	(6,852)	(4,105)	(4,215)
Other assets	(7,157)	(2,465)	(515)
Accounts payable and accrued expenses	3,756	2,245	7,273
Prepaid rent and other liabilities	262	(1,611)	2,820
Deferred rent payable	5,317	794	1,258
Net cash provided by operating activities	97,723	68,648	61,206
CASH FLOWS FROM INVESTING ACTIVITIES
Tenant improvements	(7,128)	(6,075)	(5,328)
Real estate improvements	(185,452)	(83,837)	(112,196)
Acquisition of NY2	(21,889)
Acquisition of Comfluent, net of cash received		(2,581)
Changes in reserves for capital improvements		8,691	4,965
Net cash used in investing activities	(214,469)	(83,802)	(112,559)
CASH FLOWS FROM FINANCING ACTIVITIES
Offering costs			(17)
Proceeds from exercise of stock options	925	1,564	31
Gross proceeds from the issuance of Series A Preferred Stock		115,000
Series A Preferred Stock offering costs paid	(27)	(4,190)
Proceeds from revolving credit facility	174,250	72,750	5,000
Payments on revolving credit facility		(77,750)
Proceeds from mortgage loans payable			6,440
Repayments of mortgage loans payable	(1,500)	(57,114)	(14,189)
Payments of loan fees and costs	(2,621)	(503)	(1,745)
Dividends and distributions	(57,098)	(33,101)	(23,785)
Net cash provided by (used in) financing activities	113,929	16,656	(28,265)
Net change in cash and cash equivalents	(2,817)	1,502	(79,618)
Cash and cash equivalents, beginning of period	8,130	6,628	86,246
Cash and cash equivalents, end of period	5,313	8,130	6,628
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid for interest	5,365	5,492	4,360
NON-CASH INVESTING AND FINANCING ACTIVITY
Construction costs payable capitalized to real estate	19,821	10,520	5,564
Accrual of dividends and distributions	$ 18,804	$ 13,384	$ 8,453