Income Taxes - Additional Information (Detail) - Canada $ in Millions |
Dec. 31, 2016
USD ($)
|
|---|---|
| Income Taxes [Line Items] | |
| Foreign net operating loss carryforwards | $ 7.0 |
| Foreign investment tax credit carryforwards | 0.9 |
| Accumulated earnings subject to deferred withholding tax | 57.0 |
| Unrecognized deferred withholding tax liability | $ 2.8 |