Stock-Based Compensation - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation cost related to stock grants and vesting of restricted stock units		$ 3,154
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value of restricted stock units vested and released	$ 3	1,346
Compensation cost related to stock grants and vesting of restricted stock units	1,802	3,154
Unrecognized compensation cost related to nonvested restricted stock units	15,579	$ 15,579	$ 15,721
Expected weighted-average period to be recognized		3 years 5 months 16 days	3 years 7 months 28 days
Restricted Stock Units (RSUs) \| Director
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation cost related to stock grants and vesting of restricted stock units	$ 277
EBI Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
EBI Units remaining in equity based incentive plans for employees, units	67,470	67,470	180,447
EBI Units remaining in equity based incentive plans for employees, value	$ 2,442	$ 2,442	$ 4,683
Expense related to cash settled EBI	$ 184	$ 482
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum number of shares issuable			200,000
Purchase price percentage of first offering period			85.00%
Purchase price percentage of current offering period			95.00%
Maximum number of shares per participant			725
Maximum worth of award per participant			$ 25,000
Shares issued under plan	0	0
Number of shares reserved for issuance	2,479,623	2,479,623	2,479,623

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Purchase price percentage of first offering period.

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- Definition

Share based compensation arrangement by share based payment award maximum purchase of common stock value per employee.

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- Definition

Aggregate number of common shares reserved for future issuance.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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Aggregate cash paid by the entity during the period to settle equity instruments granted under equity-based payment arrangements.

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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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Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

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The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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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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The highest quantity of shares an employee can purchase under the plan per period.

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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Number of share instruments newly issued under a share-based compensation plan.

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- Definition

Intrinsic value of equity-based compensation awards not vested. Excludes stock and unit options.

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