Consolidated and Combined Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2012	Apr. 19, 2011 STAG Predecessor Group	Dec. 31, 2010 STAG Predecessor Group
Cash flows from operating activities:
Net loss	$ (9,227)	$ (10,199)	$ (229)	$ (2,946)
Adjustment to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	22,794	43,473	2,459	9,599
Loss on impairments		4,563
Non-cash portion of interest expense	737	957	31
Intangible amortization in rental income, net	2,776	4,837	(2)	(34)
Straight-line rent adjustments, net	(1,036)	(2,796)	(16)	(641)
(Gain) loss on interest rate swaps	(2,179)	(215)	(762)	282
Loss on extinguishment of debt		929
Gain on sales of real estate	(329)	(222)
Non-cash compensation expense	693	1,936
Issuance of units for acquisition fee		225
Change in assets and liabilities:
Tenant accounts receivable, net	(695)	(1,497)	88	496
Leasing commissions, net	(877)	(1,020)	(24)	(101)
Restricted cash	(124)	(137)
Prepaid expenses and other assets	(207)	(799)	(87)	127
Accounts payable, accrued expenses and other liabilities	1,503	6,174	106	328
Tenant prepaid rent and security deposits	783	2,208	169	(860)
Due from related parties		(406)	(141)	28
Due to related parties	54		767	3,056
Total adjustments	23,893	58,210	2,588	12,280
Net cash provided by operating activities	14,666	48,011	2,359	9,334
Cash flows from investing activities:
Additions of land and building improvements	(80,191)	(325,820)	(39)	(1,500)
Proceeds from sales of real estate	4,507	7,221
Restricted cash	(1,561)	1,251	(542)	(588)
Cash paid for contributed assets, net	(2,159)
Cash paid for deal deposits, net	(130)	550
Additions to lease intangibles	(34,924)	(100,405)
Net cash used in investing activities	(114,458)	(417,203)	(581)	(2,088)
Cash flows from financing activities:
Proceeds from issuance of common stock at initial public offering	205,563
Offering costs related to issuance of common stock	(17,042)
Redemption of initial capitalization of STAG Industrial, Inc. shares	(2)
Proceeds from issuance of preferred stock	69,000
Offering costs related to issuance of preferred stock	(2,495)
Proceeds from notes payable to related parties			789
Repayment of notes payable to related parties	(10,366)
Proceeds from credit facility	34,500	124,300
Repayment of credit facility	(34,500)	(124,300)
Proceeds from unsecured credit facility		215,300
Repayment of unsecured credit facility		(116,000)
Proceeds from unsecured term loan		150,000
Proceeds from mortgage notes payable	48,339	78,067
Repayment of mortgage notes payable	(160,645)	(144,753)	(1,180)	(4,582)
Termination of swap contracts	(894)
Payment of loan fees and costs	(3,397)	(4,119)
Dividends and distributions	(12,048)	(38,606)	(2,679)	(3,869)
Proceeds from sale of common stock		242,947
Offering costs		(11,136)
Net cash provided by (used in) financing activities	116,013	371,700	(3,070)	(8,451)
Increase (decrease) in cash and cash equivalents	16,221	2,508	(1,292)	(1,205)
Cash and cash equivalents-beginning of period	277	16,498	1,567	2,772
Cash and cash equivalents-end of period	$ 16,498	$ 19,006	$ 275	$ 1,567