Related Party Transactions and Arrangements (Base Management Fees to Former Manager) (Narrative) (Details) (Former Manager [Member], USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 28, 2013	Jan. 21, 2015
Base Management Fees [Member]
Related Party Transaction [Line Items]
Waived management fees	$ 0	$ 6,100,000	$ 1,800,000
ARCT III [Member] | Management Fees To Affiliates, Reduced Base Management Fees [Member]
Related Party Transaction [Line Items]
Base management fee, percentage of unadjusted book value of assets greater than $3 billion				0.40%
ARCT III [Member] | Base Management Fees [Member]
Related Party Transaction [Line Items]
Base management fee, percentage of average unadjusted book value of real estate assets up to $3 billion				0.50%
Base management fee, percentage of average unadjusted book value of real estate assets				0.50%
Related party expenses		$ 5,000,000	$ 200,000
Subsequent Event [Member] | ARCT III [Member] | Base Management Fees [Member]
Related Party Transaction [Line Items]
Stock issued in lieu of cash for management fees, shares					388,461