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Summary of Significant Accounting Policies - Significant Estimates Used by Management in Determining Fair Values of Company's Reporting Units (Detail) | 12 Months Ended
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Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Goodwill Impairment Testing Assumptions [Line Items] |  |  |
Years of cash flows before terminal value | 5 years | 5 years | 5 years
Weighting of three approaches: |  |  |
Discounted cash flows | 70.00% | 70.00% | 70.00%
Market multiple | 15.00% | 15.00% | 15.00%
Market capitalization | 15.00% | 15.00% | 15.00%
Minimum [Member] |  |  |
Goodwill Impairment Testing Assumptions [Line Items] |  |  |
Discount rates | 12.50% | 12.00% | 12.00%
EBITDA multiples | 5.5 | 5.0 | 5.0
Maximum [Member] |  |  |
Goodwill Impairment Testing Assumptions [Line Items] |  |  |
Discount rates | 14.50% | 16.00% | 14.00%
EBITDA multiples | 7.0 | 6.5 | 6.0

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