Income Taxes - Schedule of Tax Credits That Expire Over Varying Amounts and Periods (Detail) $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2015
USD ($)
| |
| U.S. State [Member] | |
| Tax Credit Carryforward [Line Items] | |
| Tax credit Carryover | $ 19.3 |
| Canada [Member] | Foreign [Member] | |
| Tax Credit Carryforward [Line Items] | |
| Tax credit Carryover | $ 9.0 |
| Minimum [Member] | Canada [Member] | Foreign [Member] | |
| Tax Credit Carryforward [Line Items] | |
| Tax credit carryovers year of expiration | 2016 |
| Maximum [Member] | Canada [Member] | Foreign [Member] | |
| Tax Credit Carryforward [Line Items] | |
| Tax credit carryovers year of expiration | 2033 |