Property Dispositions (Details) (USD $)	0 Months Ended	12 Months Ended			0 Months Ended
	Oct. 17, 2014	Dec. 31, 2014 property		Dec. 31, 2013 single_tenant_property property	Jun. 11, 2014 multi-tenant_property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed of (in number of single-tenant properties and multi-tenant properties)				0
Number of real estate properties, held for sale		2		1
Total expected sale proceeds	$ 2,000,000,000
Net proceeds		1,300,000,000
Goodwill allocated to dispositions		210,139,000	[1]
2014 Property Dispositions [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed of (in number of single-tenant properties and multi-tenant properties)		65
Aggregate gross sales price		2,100,700,000
N/A - Billboard [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed of (in number of single-tenant properties and multi-tenant properties)		1
Multi-Tenant Properties [Member] | ARC Properties Operating Partnership, L.P. [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Agreement to sell number of properties	5
Multi-Tenant Portfolio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net proceeds		1,300,000,000
Payments of line of credit		1,200,000,000
Net loss on sale of properties		262,000,000
Goodwill allocated to dispositions		195,500,000
Multi-Tenant Portfolio [Member] | ARC Properties Operating Partnership, L.P. [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed of (in number of single-tenant properties and multi-tenant properties)	7
Aggregate gross sales price	1,900,000,000
Agreement to sell number of properties					67
Agreement, expected proceeds from sale of properties	52,300,000
Consideration liabilities assumed by purchaser		542,800,000
Affiliated Entity [Member] | 2014 Property Dispositions [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposition fees		$ 0

[1] Goodwill allocated to the cost basis of properties sold or classified as held for sale is included in loss on held for sale assets and disposition of properties, net, in the consolidated statement of operations.