Income Taxes - Additional Information (Detail) - USD ($) |
9 Months Ended | |
|---|---|---|
Sep. 30, 2018 |
Dec. 31, 2017 |
|
| Operating Loss Carryforwards [Line Items] | ||
| Other deferred tax assets, net | $ 30,000,000 | $ 23,100,000 |
| Parent Company [Member] | ||
| Operating Loss Carryforwards [Line Items] | ||
| Valuation allowance related to the portion of operating loss carryforwards | $ 77,100,000 | |
| Earliest Tax Year [Member] | ||
| Operating Loss Carryforwards [Line Items] | ||
| Tax years open for examination | 2015 | |
| Latest Tax Year [Member] | ||
| Operating Loss Carryforwards [Line Items] | ||
| Tax years open for examination | 2018 | |
| Le Mars [Member] | ||
| Operating Loss Carryforwards [Line Items] | ||
| Valuation allowance related to the portion of operating loss carryforwards | $ 264,467 | |
| Operating loss carryforwards | $ 2,000,000 | |
| Operating loss carryforwards expiration period | 2020 | |
| Operating loss carryforwards annual limitations in amount on use | $ 376,000 |