Fair Value Measurements - Additional Information (Detail) - USD ($) |
12 Months Ended | |
|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Fair Value Option Quantitative Disclosures [Line Items] | ||
| Transfers between Level 1, 2 and 3 in fair value measurement hierarchy | $ 0 | $ 0 |
| Unfunded Commitments | 9,183,000 | $ 10,242,000 |
| EGCP III [Member] | ||
| Fair Value Option Quantitative Disclosures [Line Items] | ||
| Unfunded Commitments | $ 8,613,000 | |
| End of the investment period | Oct. 12, 2016 | |
| Remaining obligation date | Oct. 12, 2023 | |