Real Estate Investments (Assets And Liabilities Assumed) (Details) (USD $)	1 Months Ended	12 Months Ended		25 Months Ended	12 Months Ended				0 Months Ended						12 Months Ended
	Dec. 31, 2010	Dec. 31, 2012 property	Dec. 31, 2011 property	Dec. 31, 2012	Dec. 31, 2012 Leases, Acquired-in-Place [Member]	Dec. 31, 2011 Leases, Acquired-in-Place [Member]	Dec. 31, 2012 Above Market Leases [Member]	Dec. 31, 2011 Above Market Leases [Member]	Jul. 03, 2012 Property in Havertown, PA [Member]	Sep. 30, 2012 Contributor [Member] ARC Real Estate Partners, LLC [Member] property	Dec. 31, 2012 Occupied [Member] property	Dec. 31, 2011 Occupied [Member] property	Dec. 31, 2012 Vacant [Member] Real Estate [Member] property	Dec. 31, 2011 Vacant [Member] Real Estate [Member] property	Dec. 31, 2012 GSA [Member]	Dec. 31, 2012 John Deere [Member]	Dec. 31, 2012 Citizens Bank [Member]	Dec. 31, 2011 Citizens Bank [Member]	Dec. 31, 2011 Home Depot [Member]	Dec. 31, 2012 IOWA	Dec. 31, 2012 SOUTH CAROLINA	Dec. 31, 2011 SOUTH CAROLINA	Dec. 31, 2012 MICHIGAN	Dec. 31, 2011 MICHIGAN	Dec. 31, 2012 OHIO	Dec. 31, 2011 OHIO	Dec. 31, 2012 Cash [Member]		Dec. 31, 2011 Cash [Member]
Real Estate Properties [Line Items]
Business Acquisition, Cost of Acquired Entity, Cash Paid		$ 17,500,000		$ 17,500,000
Operating Leases, Future Minimum Payments Receivable, Current		23,113,000		23,113,000
Acquisition related	0	3,988,000	1,875,000
Entity Wide Revenue, Major State, Percentage																				10.00%	10.60%	23.40%	15.20%	23.40%	10.80%	16.80%
Entity-Wide Revenue, Major Customer, Percentage															11.60%	10.00%	28.70%	62.90%	21.10%
Operating Leases, Future Minimum Payments Due, Next Twelve Months		160,000		160,000
Operating Leases, Future Minimum Payments Receivable, in Two Years		23,309,000		23,309,000
Business Acquisition, Pro Forma Revenue	1,932,000	23,512,000	23,512,000
Land		15,856,000	18,489,000
Buildings, fixtures and improvements		98,536,000	107,340,000
Total tangible assets		114,392,000	125,829,000
Acquired intangibles					16,096,000	11,044,000	1,264,000	0
Purchase proce of acquired real estate investments		131,752,000	136,873,000
OP units issued to acquire real estate investments	0	(6,352,000)	0
Cash paid for acquired real estate investments	0	125,400,000	17,528,000																								125,400,000	[1]	136,873,000	[1]
Number of Businesses Acquired		58	88	146
Business Acquisition, Cost of Acquired Entities Throughout Period, Purchase Price		131,752,000	136,873,000	268,625,000
Number Of Properties Contributed By Affiliate										63
Number of Real Estate Properties											147	90	1	2
Proceeds from sale of property held for sale	0	553,000	0						600,000
Business Acquisition, Pro Forma Net Income (Loss)	(3,776,000)	(824,000)	724,000
Operating Leases, Future Minimum Payments Receivable, in Three Years		23,153,000		23,153,000
Operating Leases, Future Minimum Payments Receivable, in Four Years		22,808,000		22,808,000
Operating Leases, Future Minimum Payments Receivable, in Five Years		18,761,000		18,761,000
Operating Leases, Future Minimum Payments, Due Thereafter		50,031,000		50,031,000
Total		161,175,000		161,175,000
Operating Leases, Future Minimum Payments, Due in Two Years		160,000		160,000
Operating Leases, Future Minimum Payments, Due in Three Years		160,000		160,000
Operating Leases, Future Minimum Payments, Due in Four Years		160,000		160,000
Operating Leases, Future Minimum Payments, Due in Five Years		160,000		160,000
Operating Leases, Future Minimum Payments, Due Thereafter		600,000		600,000
Operating Leases, Future Minimum Payments Due		$ 1,400,000		$ 1,400,000

[1] (1) For the year ended December 31, 2011, the amount includes the properties that were contributed in September 2011 in conjunction with the completion of the IPO by the Contributor at amortized cost as well as $17.5 million of properties acquired by the Company following the IPO.