Mergers with Real Estate Businesses - Cole Credit Property Trust, Inc. Merger (Details) - Cole Credit Property Trust, Inc. [Member] - USD ($) $ / shares in Units, $ in Thousands			12 Months Ended
	May 20, 2014	May 19, 2014	Dec. 31, 2014
Business Acquisition [Line Items]
Consideration transferred		$ 73,200
Consideration transferred, amount per share (in dollars per share)		$ 7.25
Consideration transferred and paid in cash		$ 73,159
Estimated fair value of assets		159,514
Estimated fair value of liabilities		$ 1,752
Revenue related to merger			$ 8,200
Net loss related to merger			$ 1,800
Common Stock [Member]
Business Acquisition [Line Items]
Shares tendered and not withdrawn (shares)		7,735,069
Percentage of shares outstanding	90.00%	77.00%
Shares issued (shares)	13,457,874
Number of shares more than 90% of outstanding shares (shares)	1