American Realty Capital Trust, Inc. (ARCT) (Details) (USD $)	0 Months Ended
	Jan. 22, 2013 item	Sep. 30, 2013	Dec. 31, 2012
Noncontrolling Interests
Number of properties		3,866
Carrying value of preferred units		$ 6,750,000
Tau Operating Partnership, L.P.
Noncontrolling Interests
Partnership units, ownership interest (as a percent)	99.30%
Payment rate per annum (as a percent)	2.00%
Carrying value of preferred units		6,750,000
ARCT
Acquisition of American Realty Capital Trust, Inc.
Transaction value	3,200,000,000
Cash paid for common stock on acquisition (in dollars per share)	$ 0.35
Common stock conversion ratio	0.2874
Common stock issued to shareholders of acquiree (in shares)	45,573,144
Closing price of common stock (in dollars per share)	$ 44.04
Repayment of amount outstanding under ARCT's revolving credit facility and term loan	552,900,000
Number of properties added to portfolio	515
Preliminary purchase price of the ARCT acquisition
Consideration associated with equity issued	2,027,753,000
Cash consideration paid to previous owners of ARCT	56,216,000
Total purchase consideration	2,083,969,000
Assets:
Real estate	2,672,053,000
Acquired lease intangible assets	562,339,000
Cash and cash equivalents, accounts receivable, and other assets, net	42,275,000
Total Assets	3,276,667,000
Liabilities:
Lines of credit payable	317,207,000
Term loan	235,000,000
Mortgages payable	538,960,000
Acquired lease intangible liabilities	78,711,000
Accounts payable, accrued expenses, and other liabilities, net	22,820,000	29,600,000
Total Liabilities	1,192,698,000
Estimated fair value of net assets acquired	2,083,969,000
Transaction Costs
Estimated total merger-related transaction costs		21,000,000
Total merger-related transaction costs		$ 12,900,000	$ 7,900,000