Summary of Significant Accounting Policies - Narrative (Details) |
6 Months Ended | |
|---|---|---|
|
Jun. 30, 2017
USD ($)
segment
|
Dec. 31, 2016
USD ($)
|
|
| Summary Of Significant Accounting Policies [Line Items] | ||
| Net assets | $ 7,519,323,000 | $ 7,677,971,000 |
| Net liabilities | $ 4,163,490,000 | 3,995,863,000 |
| Number of segments | segment | 1 | |
| Reserves for uncollectible amounts | $ 10,200,000 | 6,400,000 |
| Accounts receivable | 23,800,000 | 25,300,000 |
| Reserve for losses | 4,300,000 | 7,700,000 |
| Deferred rental revenue receivables | 76,600,000 | 71,100,000 |
| Provision for income taxes | 0 | |
| Special Purpose Entity | ||
| Summary Of Significant Accounting Policies [Line Items] | ||
| Net assets | 2,830,000,000 | 2,950,000,000 |
| Net liabilities | $ 2,200,000,000 | $ 2,260,000,000 |