Notes Receivable - Additional Information (Detail) - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Accounts Notes And Loans Receivable [Line Items] | ||
| Notes receivable | $ 6,527 | $ 6,527 |
| 7.00% Loan Agreement | ||
| Accounts Notes And Loans Receivable [Line Items] | ||
| Notes receivable | 3,700 | |
| Real Estate | ||
| Accounts Notes And Loans Receivable [Line Items] | ||
| Interest income earned | $ 445 | 77 |
| Real Estate | 7.00% Loan Agreement | ||
| Accounts Notes And Loans Receivable [Line Items] | ||
| Notes receivable | $ 3,700 | |
| Interest rate | 7.00% | |
| Maturity date | 2019-02 | |
| Real Estate | 6.35% Loan Agreement | ||
| Accounts Notes And Loans Receivable [Line Items] | ||
| Notes receivable | $ 2,827 | |
| Interest rate | 6.35% | |
| Maturity date | 2019-11 | |