|
Investments - Narrative (Details) (USD $)
|
3 Months Ended | ||
|---|---|---|---|
|
Mar. 31, 2015
State
Property
|
Mar. 31, 2014
|
Dec. 31, 2014
Property
|
|
| Investment [Line Items] | |||
| Gross investment in real estate properties | $ 8,226,205,000 | $ 8,044,363,000 | |
| Number of real estate properties | 2,547 | 2,509 | |
| Number of properties securing borrowings | 145 | ||
| Properties dispersed geographically | 49 | ||
| Minimum percentage of investment in real estate properties | 10.00% | ||
| Amortization amount to rental revenue for capitalized leases | 1,400,000 | 1,300,000 | |
| Texas | |||
| Investment [Line Items] | |||
| Number of states exceeding disclosure threshold | 1 | ||
| Percentage of investment in real estate properties | 11.90% | ||
| In-Place Leases | |||
| Investment [Line Items] | |||
| Leases amortization expenses | $ 12,800,000 | $ 13,400,000 | |