Investments - Summary of Real Estate and Loan Activity, Net of Accumulated Depreciation and Amortization (Footnote) (Details) $ in Millions |
6 Months Ended | |
|---|---|---|
|
Jun. 30, 2015
USD ($)
Property
|
Dec. 31, 2014
Property
|
|
| Real Estate Properties [Line Items] | ||
| Revenue producing capitalized expenditures | $ 2.6 | |
| Capitalized maintenance expenditures | 0.6 | |
| Accumulated depreciation and amortization associated with dispositions of real estate | $ 73.7 | |
| Number of properties sold under 1031 Exchanges | Property | 23 | |
| Amount of properties sold under 1031 Exchanges | $ 212.1 | |
| Amount of properties acquired under 1031 Exchanges | $ 172.1 | |
| Number of properties acquired under 1031 Exchanges | Property | 62 | |
| Properties Vacant | ||
| Real Estate Properties [Line Items] | ||
| Number of properties | Property | 33 | 37 |
| Property Held For Sale | ||
| Real Estate Properties [Line Items] | ||
| Number of properties | Property | 11 | 8 |