Summary of Significant Accounting Policies - Narrative (Details) |
6 Months Ended | 12 Months Ended |
|---|---|---|
|
Jun. 30, 2015
USD ($)
segment
|
Dec. 31, 2014
USD ($)
|
|
| Summary Of Significant Accounting Policies [Line Items] | ||
| Net assets | $ 7,929,239,000 | $ 7,970,669,000 |
| Net liabilities | $ 4,317,900,000 | 4,652,568,000 |
| Number of segments | segment | 1 | |
| Reserves for uncollectible amounts | $ 8,100,000 | 8,400,000 |
| Accounts receivable | 25,100,000 | 20,500,000 |
| Provision for losses | 9,400,000 | 10,900,000 |
| Deferred rental revenue receivables | 56,300,000 | 48,300,000 |
| Provision for income taxes | 0 | |
| Accounting Standards Update 2015-03 | Adjustments for New Accounting Principle, Early Adoption | ||
| Summary Of Significant Accounting Policies [Line Items] | ||
| Amount of reclassification of unamortized deferred financing costs now included as reduction of debt | 46,300,000 | |
| Special Purpose Entity | ||
| Summary Of Significant Accounting Policies [Line Items] | ||
| Net assets | 4,880,000,000 | 5,680,000,000 |
| Net liabilities | $ 3,420,000,000 | $ 3,770,000,000 |