Stock-based Compensation - Additional Information 1 (Detail) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2016 USD ($) Unit $ / shares $ / EquityUnit shares	Dec. 31, 2015 USD ($) Unit $ / shares $ / EquityUnit shares	Dec. 31, 2014 USD ($) Unit $ / shares $ / EquityUnit
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance multiplier, minimum	0.00%
Performance multiplier, maximum	200.00%
Number of Options Outstanding \| shares	0	11,730
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense recognized	$ 3.4	$ 6.0	$ 7.3
Grant date fair value of share units, per share \| $ / shares	$ 5.46	$ 26.70	$ 101.20
Unrecognized compensation cost related to unvested restricted stock	$ 2.8
Period in which compensation cost expected to be recognized	1 year 4 months 24 days
Fair value of restricted stock vested	$ 1.3	$ 3.7	$ 10.0
Potential Performance Shares (PSU)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense recognized	$ 1.3	$ 2.1	$ 3.4
Performance Periods	The performance periods consist of one year, two years and three years, respectively
Number of units granted \| Unit	60,015	94,250	37,792
Grant date fair value of performance share units, granted	$ 0.4	$ 0.7	$ 3.7
Grant date fair value of share units, per unit \| $ / EquityUnit	7.00	7.30	99.05
Minimum final number of shares of common stock issuable based on performance multiplier \| shares	0
Maximum final number of shares of common stock issuable based on performance multiplier \| shares	269,300
Performance multiplier, minimum	0.00%
Performance multiplier, maximum	200.00%
Unrecognized expense, performance share units	$ 1.1
Term for Amortization of Performance Share Compensation cost	through December 31, 2017.
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Options Outstanding \| shares	0
Minimum \| Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Amortized vesting period of restricted stock	1 year
Minimum \| Potential Performance Shares (PSU)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Amortized vesting period of restricted stock	1 year
Maximum \| Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Amortized vesting period of restricted stock	3 years
Maximum \| Potential Performance Shares (PSU)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Amortized vesting period of restricted stock	3 years

Amortization term related to performance shares.

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Final Number Of Potential Performance Shares Issuable Maximum.

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Grant date fair value of performance share units.

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Number of performance share units awards granted.

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Performance periods.

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Performance units adjustment for performance multiplier range maximum.

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Performance units adjustment for performance multiplier range minimum.

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Share based compensation arrangement by share based payment award equity instruments other than options grant date fair value.

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Share based compensation arrangement by share based payment award equity instruments other than options unrecognized compensation cost.

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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Unrecognized cost of unvested share-based compensation awards.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Number of options outstanding, including both vested and non-vested options.

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