Summary of Significant Accounting Policies - Summary of Financing Receivables (Detail) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Financing Receivable, Recorded Investment [Line Items] | ||
| Advances to equity accounted investments | $ 10,480 | $ 13,980 |
| Other Internal Metrics [Member] | Performing [Member] | ||
| Financing Receivable, Recorded Investment [Line Items] | ||
| Advances to equity accounted investments | $ 10,480 | $ 13,980 |