Consolidated and Combined Statements of Stockholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Total Stockholder's Equity	Preferred Stock	Common Shares	Additional Paid in Capital	Common Stock Dividends in Excess of Earnings	Noncontrolling Interest - Unit Holders in Operating Partnership	STAG Predecessor Group	STAG Predecessor Group Total Stockholder's Equity	STAG Predecessor Group Owner's Deficit
Balance at Dec. 31, 2010								$ (8,336)	$ (8,336)	$ (8,336)
Increase (Decrease) in Stockholders' Equity
Contributions								4,420	4,420	4,420
Distributions								(9,900)	(9,900)	(9,900)
Net income (loss)								(229)	(229)	(229)
Balance at Apr. 19, 2011	(14,043)	(14,043)			2					(14,045)
Balance (in shares) at Apr. 19, 2011				110
Balance at Apr. 19, 2011								(14,045)	(14,045)	(14,045)
Balance at Mar. 31, 2011
Increase (Decrease) in Stockholders' Equity
Net income (loss)								(89)
Balance at Apr. 19, 2011	(14,043)	(14,043)			2
Balance (in shares) at Apr. 19, 2011				110
Balance at Apr. 19, 2011								(14,045)
Balance at Apr. 20, 2011
Increase (Decrease) in Stockholders' Equity
Proceeds from sale of common stock	205,563	205,563		158	205,405
Proceeds from sale of common stock (in shares)				15,812,500
Redemption of initial capitalization of STAG Industrial, Inc.	(2)	(2)			(2)
Redemption of initial capitalization of STAG Industrial, Inc. (in shares)				(110)
Issuance of units for acquisition of properties	95,670						95,670
Exchange of owners' equity for units		14,045					(14,045)			14,045
Offering costs	(17,042)	(17,042)			(17,042)
Issuance of restricted stock				1	(1)
Issuance of restricted stock (in shares)				80,809
Dividends and distributions	(4,871)	(3,269)				(3,269)	(1,602)
Stock-based compensation	156	39			39		117
Rebalancing of noncontrolling interest		(7,226)			(7,226)		7,226
Net income (loss)	(5,899)	(3,903)				(3,903)	(1,996)
Balance at Jun. 30, 2011	259,532	174,162		159	181,175	(7,172)	85,370
Balance (in shares) at Jun. 30, 2011				15,893,309
Balance at Dec. 31, 2011	309,909	230,693	69,000	159	179,919	(18,385)	79,216
Balance (in shares) at Dec. 31, 2011				15,901,560
Increase (Decrease) in Stockholders' Equity
Proceeds from sale of common stock	107,387	107,387		83	107,304
Proceeds from sale of common stock (in shares)				8,337,500
Offering costs	(5,104)	(5,104)			(5,104)
Issuance of restricted stock				1	(1)
Issuance of restricted stock (in shares)				87,025
Issuance of common stock (in shares)				8,241
Dividends and distributions	(18,136)	(14,003)	(3,106)			(10,897)	(4,133)
Stock-based compensation	976	502			502		474
Issuance of units for acquisition fee	225						225
Conversion of operating partnership units to common stock		6,044		6	6,038		(6,044)
Conversion of operating partnership units to common stock (in shares)				623,932
Rebalancing of noncontrolling interest		(5,989)			(5,989)		5,989
Net income (loss)	(2,889)	(1,036)	3,106			(4,142)	(1,853)
Balance at Jun. 30, 2012	$ 392,368	$ 318,494	$ 69,000	$ 249	$ 282,669	$ (33,424)	$ 73,874
Balance (in shares) at Jun. 30, 2012				24,958,258