Variable Interest Entities - Textuals (Details) - Variable Interest Entity, Primary Beneficiary, Aggregated Disclosure [Member] - entity |
12 Months Ended | |
---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
|
Variable Interest Entity [Line Items] | ||
Number of consolidated limited partnership-like entities | 8 | 10 |
Minimum [Member] | ||
Variable Interest Entity [Line Items] | ||
Ownership interest in the consolidated entities (percent) | 50.00% | |
Maximum [Member] | ||
Variable Interest Entity [Line Items] | ||
Ownership interest in the consolidated entities (percent) | 75.00% |