Mergers with Real Estate Businesses (American Realty Capital Trust III, Inc. Merger) (Narrative) (Details) - Member Units [Member] - ARCT III [Member] $ / shares in Units, shares in Millions, $ in Millions	Feb. 28, 2013 USD ($) $ / shares shares
Business Acquisition [Line Items]
Conversion of common stock (shares)	0.95
Consideration transferred, amount per share (in dollars per share) | $ / shares	$ 12.00
Aggregate cash paid | $	$ 350.4
Value of acquired shares exchanged for cash	29.2
Percentage of shares outstanding	16.50%
Value of acquiree shares equivalent to acquirer shares	27.7
Additional units issued (shares)	140.7
Value of acquiree shares exchanged for acquirer shares	148.1
American Realty Capital III Special Limited Partnership LLC [Member]
Business Acquisition [Line Items]
Additional units issued (shares)	7.3
Minimum holding period	1 year