Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 19.8
Period of expense of unrecognized compensation cost, years	2 years 10 months 24 days
Common stock reserved for future issuance (in shares)	3,300,000
Shares available for future grant (in shares)	800,000
Maximum term of grants	10 years
Options vested and exercisable, period	5 years
Weighted average grant-date fair value of stock options granted (in dollars per share)	$ 8.18	$ 10.48
Aggregate intrinsic value of stock options exercised	$ 1.5	$ 4.7
Average weekly hours of work	20 hours
Stock options authorized to issue to employees (in shares)	2,200,000
SERP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance (in shares)	1,000,000.0
Remaining shares authorized for issuance (in shares)	400,000
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock granted (in shares)	200,000	100,000
Weighted average grant date fair value of restricted stock granted (in dollars per share)	$ 40.49	$ 52.06
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock granted (in shares)	0	0
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Requisite service period for plan participation eligibility	2 years
Stock options authorized to issue to employees (in shares)	4,100,000

Deferred Compensation Arrangement with Individual, Remaining Shares Authorized for Issuance

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Maximum Term of Grants.

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Average Weekly Hours of Work

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- Definition

Aggregate number of common shares reserved for future issuance.

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-Name Accounting Standards Codification
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- Definition

The maximum number of shares authorized for issuance under the deferred compensation arrangement as of the balance sheet date.

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- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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The number of grants made 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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- Definition

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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- Definition

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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- Definition

Number of shares authorized for issuance under share-based payment arrangement.

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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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- Definition

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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