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Employee Benefit Plans - Composition of Pension Plan Assets by Fair Value Level (Detail) - USD ($) $ in Thousands | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
--- | --- | --- | ---
U.S. Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total | $ 31,937 | $ 33,573 |
U.K. plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total | 10,331 | 10,494 |
Defined Benefit Pension Plans |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total | 42,268 | 44,067 | $ 48,816
CMRT | U.S. Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total | 31,937 | 33,573 |
Other | U.K. plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total | 10,331 | 10,494 |
Level 1 | Defined Benefit Pension Plans |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total | 10,331 | 10,494 |
Level 1 | Other | U.K. plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total | 10,331 | 10,494 |
Level 2 | Defined Benefit Pension Plans |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total | 31,937 | 33,573 |
Level 2 | CMRT | U.S. Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Total | $ 31,937 | $ 33,573 |

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