Employee Benefit Plans - Additional Information (Detail) - USD ($)
$ in Millions |
12 Months Ended |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
| Defined Benefit Plan Disclosure [Line Items] |
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| Defined contribution benefit plan expense |
$ 2.8
|
$ 2.7
|
$ 2.6
|
| Defined Benefit Pension Plans |
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| Defined Benefit Plan Disclosure [Line Items] |
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| Expected contributions next fiscal year |
14.8
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| Unrecognized actuarial losses to be recognized in next fiscal year |
12.8
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| Unrecognized prior service cost to be recognized in next fiscal year |
$ 0.2
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| United States Pension Plans of US Entity, Defined Benefit |
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| Defined Benefit Plan Disclosure [Line Items] |
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| Discount rate |
3.90%
|
4.10%
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| Expected long-term rate of return |
7.50%
|
7.50%
|
7.50%
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| United States Pension Plans of US Entity, Defined Benefit | CMRT |
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| Defined Benefit Plan Disclosure [Line Items] |
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| Expected long-term rate of return |
7.50%
|
7.50%
|
7.50%
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| United States Pension Plans of US Entity, Defined Benefit | CMRT | Level 1 and Level 2 |
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| Defined Benefit Plan Disclosure [Line Items] |
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| Percentage of fair value of asset |
92.00%
|
91.00%
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| Foreign Pension Plans, Defined Benefit |
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| Defined Benefit Plan Disclosure [Line Items] |
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| Discount rate |
2.10%
|
2.60%
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| Expected long-term rate of return |
3.90%
|
4.60%
|
5.00%
|
| Foreign Pension Plans, Defined Benefit | Equity Securities | Canada |
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| Defined Benefit Plan Disclosure [Line Items] |
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| Target asset allocation |
35.00%
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| Average basis points of long-term rate of return on investment |
125 basis points above the applicable equity or fixed income index
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| Foreign Pension Plans, Defined Benefit | Equity Securities | Norway |
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| Defined Benefit Plan Disclosure [Line Items] |
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| Expected long-term rate of return |
7.00%
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| Target asset allocation |
11.00%
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| Foreign Pension Plans, Defined Benefit | Debt Securities | Canada |
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| Defined Benefit Plan Disclosure [Line Items] |
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| Target asset allocation |
65.00%
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| Average basis points of long-term rate of return on investment |
125 basis points above the applicable equity or fixed income index
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| Foreign Pension Plans, Defined Benefit | Debt Securities | Norway |
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| Defined Benefit Plan Disclosure [Line Items] |
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| Expected long-term rate of return |
3.00%
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| Target asset allocation |
79.00%
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| Foreign Pension Plans, Defined Benefit | Other Investment Securities And Cash | Canada |
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| Defined Benefit Plan Disclosure [Line Items] |
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| Average basis points of long-term rate of return on investment |
125 basis points above the applicable equity or fixed income index
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| Foreign Pension Plans, Defined Benefit | Other Investment Securities And Cash | Norway |
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| Defined Benefit Plan Disclosure [Line Items] |
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| Expected long-term rate of return |
7.00%
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| Foreign Pension Plans, Defined Benefit | Real Estate | Norway |
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| Defined Benefit Plan Disclosure [Line Items] |
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| Expected long-term rate of return |
5.00%
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| Target asset allocation |
7.00%
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| Foreign Pension Plans, Defined Benefit | Real Estate And Other Investments | Norway |
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| Defined Benefit Plan Disclosure [Line Items] |
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| Actual plan asset allocation |
11.00%
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